A rule of thumb for speed of sound is approximately 750 miles per hour at sea level and approximately 660 miles per hour at 30,000 feet above sea level.

A body traveling at Mach 1 would be traveling at the speed of sound. Mach 2 would equal twice the speed of sound.

Check the masthead if in doubt.

Plurality means more than the next highest number.

COMPUTING MAJORITY: To describe how large a majority is, take the figure that is more than half and subtract everything else from it: If 100,000 votes were cast in an election and one candidate received 60,000 while opponents received 40,000, the winner would have a majority of 20,000 votes.

COMPUTING PLURALITY: To describe how large a plurality is, take the highest number and subtract from it the next highest number: If, in the election example above, the second-place finisher had 25,000 votes, the winner’s plurality would be 35,000 votes.

Suppose, however, that no candidate in this example had a majority. If the first-place finisher had 40,000 votes and the second-place finisher had 30,000, for example, the leader’s plurality would be 10,000 votes.

USAGE: When majority and plurality are used alone, they take singular verbs and pronouns: The majority has made its decision.

If a plural word follows an of construction, the decision on whether to use a singular or plural verb depends on the sense of the sentence: A majority of two votes is not adequate to control the committee. The majority of the houses on the block were destroyed.

Frequently the best choice is a substitute such as humanity, a person or an individual.

Do not capitalize in job descriptions such as equipment manager John Smith.

In New Orleans and many Roman Catholic countries, the Tuesday celebration is preceded by a week or more of parades and parties.

Capitalize Marine when referring to an individual in a Marine Corps unit: He is a Marine.

Marshall is used in proper names: George C. Marshall, John Marshall, the Marshall Islands.

In datelines, give the name of a city and Marshall Islands. List the name of an individual island in the text.

In Eastern Orthodox churches the correct term is Divine Liturgy.

Mayday is the international distress signal, from the French m’aidez, a reflexive verb meaning “help me.”

There is no Congressional Medal of Honor.

A state determines eligibility and which health services are covered. The federal government reimburses a percentage of the state’s expenditures.

Medicare helps pay charges for hospitalization, for stays in skilled nursing facilities, for physician’s charges and for some associated health costs. There are limitations on the length of stay and type of care.

In Canada, Medicare refers to the nation’s national health insurance program.

Examples: 33rd meridian (if location east or west of Greenwich is obvious), 1st meridian west, 100th meridian.

It is equal to approximately 39.37 inches, which may be rounded off to 39.5 inches in most comparisons.

It takes 100 centimeters to make a meter.

It takes 1,000 meters to make a kilometer.

To convert to inches, multiply by 39.37 (5 meters x 39.37 = 196.85 inches).

To convert to yards, multiply by 1.1 (5 meters x 1.1 = 5.5 yards).

The principal Methodist body in the United States is the United Methodist Church, which also has some member conferences outside the United States. It was formed in 1968 by the merger of the Methodist Church and the Evangelical United Brethren Church. It has about 10 million members.

The government of the United Methodist Church follows a stratified pattern from the General Conference through several intermediate conferences down to the local congregation.

The General Conference, which meets every four years, has final authority in all matters. Its members, half lay and half clergy, are elected by the annual conferences.

A Methodist bishop presides over a “church area,” which may embrace one or more annual conferences. Bishops have extensive administrative powers, including the authority to place, transfer and remove local church pastors, usually in consultation with district superintendents.

Districts in each conference are responsible for promotion of mission work, support of colleges, hospitals and publications, and examination of candidates for the ministry.

Members of a congregation form a charge conference. It elects officers to a board that assists the pastor.

Methodism in the United States also includes three major black denominations: the African Methodist Episcopal Church, the African Methodist Episcopal Zion Church and the Christian Methodist Episcopal Church.

Methodists believe in the Trinity and the humanity and divinity of Christ. There are two sacraments, baptism and the Lord’s Supper.

Ordained individuals are known as bishops and ministers. Pastor applies if a minister leads a congregation.

For first references to bishops use the word: Bishop W. Kenneth Goodson of Richmond, Va.

For first reference to ministers, use the Rev. before the name of a man or woman. On second reference, use only the last name of a man; use Miss, Mrs., Ms., or no title before the last name of a woman depending on her preference.

There are no hard-and-fast rules on when they are relevant, but the following two guidelines have been developed to cover questions likely to arise as metric measurements gain increased acceptance in the United States:

—Use metric terms when they are the primary form in which the source of a story has provided statistics. Follow the metric units with equivalents in the terms more widely known in the United States. Normally, the equivalent should be in parentheses after the metric figure. A general statement such as: A kilometer equals about five-eighths of a mile, would be acceptable, however, to avoid repeated use of parenthetical equivalents in a story that uses kilometers many times.

—Provide metric equivalents for traditional forms if a metric unit has become widely known. As speedometers with kilometer markings become more prevalent, for example, a story about speed limits might list miles per hour and provide kilometers per hour in parentheses.

CONVERSION FORMULAS: A conversion table for frequently used metric terms follows.

To avoid the need for long strings of figures, prefixes are added to the metric units to denote fractional elements or large multiples. The prefixes are: pico- (one-trillionth), nano- (one-billionth), micro- (one-millionth), milli- (one-thousandth), centi- (one-hundredth), deci- (one-tenth), deka- (10 units), hecto- (100 units), giga- (1 billion units), tera- (1 trillion units). Entries for each prefix show how to convert a unit preceded by the prefix to the basic unit.

ABBREVIATIONS: The abbreviation mm for millimeter is acceptable in references to film widths (8 mm film) and weapons (a 105 mm cannon). (Note space between numeral and abbreviation.)

Do not otherwise use metric abbreviations in news copy.

The principal abbreviations, for reference in the event they are used by a source, are: g (gram), kg (kilogram), t (metric ton), m (meter), cm (centimeter), km (kilometer), mm (millimeter), L (liter, capital L to avoid confusion with the figure 1) and mL (milliliter).

Headquarters is in Culver City, Calif.

Move a decimal point six places to the left in converting to the basic unit: 2,999,888.5 microseconds = 2.9998885 seconds.

But use a hyphen when mid- precedes a figure: mid-30s.

Less formal references often consider Delaware part of the group.

Popular usage once distinguished between the Near East (the westerly nations in the listing) and the Middle East (the easterly nations), but the two terms now overlap, with current practice favoring Middle East for both areas.

Use Middle East unless Near East is used by a source in a story.

Mideast is also acceptable, but Middle East is preferred.

Particular care should be taken to include middle initials in stories where they help identify a specific individual. Examples include casualty lists and stories naming the accused in a crime.

A middle initial may be dropped if a person does not use one or is publicly known without it: Mickey Mantle (not Mickey C.), the Rev. Billy Graham (not Billy F.).

The shortened form Midwest is acceptable in all references.

The forms for adjectives are Middle Western, Midwestern.

The forms: MiG-19, MiG-21s.

The metric equivalent is approximately 1.6 kilometers.

To convert to kilometers, multiply by 1.6 (5 miles x 1.6 equals 8 kilometers).

Use figures for amounts under 10 in dimensions, formulas and speeds: The farm measures 5 miles by 4 miles. The car slowed to 7 mph. The new model gets 4 miles more per gallon.

Spell out below 10 in distances: He drove four miles.

Lowercase academy whenever it stands alone.

Cadet is the proper title on first reference for men and women enrolled at the Army, Air Force and Coast Guard academies. Midshipman is the proper title for men and women enrolled at the Naval Academy.

Use the appropriate title on first reference. On second reference to a man, use his last name; on second reference to a woman, use Miss, Ms., Mrs. or no title before her last name depending on her preference.

See the lists that follow to determine whether the title should be spelled out or abbreviated in regular text. Spell out any title used before a name in a direct quotation.

On first reference, use the appropriate title before the full name of a member of the military.

In subsequent references, do not continue using the title before a name. Use only the last name of a man. Use Miss, Mrs., Ms. or no title before the last name of a woman depending on her preference.

Spell out and lowercase a title when it is substituted for a name: Gen. John J. Pershing arrived today. An aide said the general would review the troops.

In some cases, it may be necessary to explain the significance of a title: Army Sgt. Maj. John Jones described the attack. Jones, who holds the Army’s highest rank for enlistees, said it was unprovoked.

In addition to the ranks listed on the next page, each service has ratings such as machinist, radarman, torpedoman, etc., that are job descriptions. Do not use any of these designations as a title on first reference. If one is used before a name in a subsequent reference, do not capitalize or abbreviate it.

ABBREVIATIONS: The abbreviations, with the highest ranks listed first:

MILITARY TITLES

MARINE CORPS

Ranks and abbreviations for commissioned officers are the same as those in the Army. Warrant officer ratings follow the same system used in the Navy. There are no specialist ratings.

Ranks and abbreviations for commissioned officers are the same as those in the Army.

PLURALS: Add s to the principal element in the title: Majs. John Jones and Robert Smith; Maj. Gens. John Jones and Robert Smith; Spcs. John Jones and Robert Smith.

RETIRED OFFICERS: A military rank may be used in first reference before the name of an officer who has retired if it is relevant to a story. Do not, however, use the military abbreviation Ret.

Instead, use retired just as former would be used before the title of a civilian: They invited retired Army Gen. John Smith.

FIREFIGHTERS, POLICE OFFICERS: Use the abbreviations listed here when a military-style title is used before the name of a firefighter or police officer outside a direct quotation. Add police or fire before the title if needed for clarity: police Sgt. William Smith, fire Capt. David Jones.

Spell out titles such as detective that are not used in the armed forces.

But: the division, the battalion, the artillery, the fleet.

Equal to approximately one-twenty-eight-thousandth of an ounce.

To convert to ounces, multiply by 0.000035 (140 milligrams x 0.000035 equals 0.0049 ounces).

Equal to approximately one-fifth of a teaspoon.

Thirty milliliters equals 1 fluid ounce.

To convert to teaspoons, multiply by .2 (5 milliliters x .2 equals 1 teaspoon).

It takes 10 millimeters to make a centimeter.

A millimeter is roughly equal to the thickness of a paper clip.

To convert to inches, multiply by .04 (5 millimeters x .04 is .2 of an inch).

May be abbreviated as mm when used with a numeral in first or subsequent references to film or weapons: 35 mm film, 105 mm artillery piece. (Note space after numeral.)

Do not go beyond two decimal places: 7.51 million people, $256 billion, 7,542,500 people, $2,565,750,000. Decimals are preferred where practical: 1.5 million. Not: 1 1/2 million.

Do not mix millions and billions in the same figure: 2.6 billion. Not: 2 billion 600 million.

Do not drop the word million or billion in the first figure of a range: He is worth from $2 million to $4 million. Not: $2 to $4 million, unless you really mean $2.

Note that a hyphen is not used to join the figures and the word million or billion, even in this type of phrase: The president submitted a $300 billion budget.

Use a word, not a minus sign, to indicate temperatures below zero: minus 10 or 5 below zero.

Explain in the text that a MIRV is an intercontinental ballistic missile with several warheads, each of which can be directed to a different target.

Mobil Oil Corp. is a subsidiary.

The Monaco section stands alone in datelines. The other two sections, La Condamine and Monte Carlo, are followed by Monaco:

When a phrase lists only a month and a year, do not separate the year with commas. When a phrase refers to a month, day and year, set off the year with commas.

EXAMPLES: January 1972 was a cold month. Jan. 2 was the coldest day of the month. His birthday is May 8. Feb. 14, 1987, was the target date.

In tabular material, use these three-letter forms without a period: Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec.

See the entry under the formal name.

Or simply: the Appalachians, the Ozarks, the Rockies.

G — General audiences. All ages admitted.

PG — Parental guidance suggested. Some material may not be suitable for children.

PG-13 — Special parental guidance strongly suggested for children under 13. Some material may be inappropriate for young children.

R — Restricted. Under 17 requires accompanying parent or adult guardian.

NC-17 — No one under 17 admitted.

When the ratings are used in news stories or reviews, use these forms as appropriate: the movie has an R rating, an R-rated movie, the movie is R-rated.

These abbreviated spellings apply in all uses, including direct quotations.

There is no plural. If several women who prefer Ms. must be listed in a series, repeat Ms. before each name.

Use quotation marks for non-musical terms in a title: Beethoven’s “Eroica” Symphony. If the work has a special full title, all of it is quoted: “Symphonie Fantastique,” “Rhapsody in Blue.”

In subsequent references, lowercase symphony, concerto, etc.

A Black Muslim is a member of a predominantly black Islamic sect in the United States. However, the term is considered derogatory by members of the sect, who call themselves Muslims.