Microsoft® Manual of Style, Fourth Edition

A

A.M., P.M.

International considerations

To accommodate the worldwide audience, use the 24-hour time notation if you can. Use 00:00, not 24:00, to indicate midnight. If you must use A.M. and P.M., use capital letters and periods.

Using 12:00 A.M. or 12:00 P.M. to refer to noon or midnight is confusing. If you are consistently using 24-hour notation, 00:00 and 12:00 are unambiguous. In any case, just specifying noon or midnight is sufficient.

Microsoft style

The meeting is at noon.

The show begins at 19:00 Pacific Time (UTC-8).

The date changes at exactly midnight.

See also midnight, Time zones.

-able, -ible

Adjectives ending in -able or -ible take their meaning from the passive sense of the stem verb from which they are formed. For example, forgettable ...