abbr. in the morning

abbr. 午前，上午：[钟点+ a.m.] School starts at 8 a.m. 学校上午8点开始上课。

常犯错误

✗ It's 7 a.m. in the morning.

✗ It's 7 o'clock a.m.

✓ It's 7 a.m. 现在是上午7点。

[✌o'clock不能与a.m.连用]

用法也可写作am，但为了与系动词am区别，多写作a.m.；也有少数人写作A.M.或AM。