More Ledes: Write With (AP) Style

Is it 9:00 a.m. or 9 a.m. or 9 am or 9 o'clock?

It's 9 a.m., or maybe 9 o'clock. Under times:

Use figures except for noon and midnight. Use a colon to separate hours from minutes: 11 a.m., 1 p.m., 3:30 p.m. . . . The construction 4 o'clock is acceptable, but time listings with a.m. or p.m. are preferred.

In the wake of this exercise, please be sure to review the AP Style listings for times.

Also, is it miles per hour or mph or m.p.h.?

It's mph or miles per hour. In AP Style, under, mph: Acceptable in all references for miles per hour or miles an hour.

Please note AP Style for mph.