Should AM or PM be capitalized?

Related questions

1. Is 10 am morning or night?
2. Does Washington DC have two periods?
3. How do you write PM?
4. Is midnight at the beginning or end of a day?
5. Do you put a space before AM or PM?
6. Does midnight belong to today or tomorrow?
7. Is 4am a midnight?
8. What is AM and PM short for?
9. How do you convert 12 hour to 24 hour time?
10. Do AM and PM have periods?

Tags

1. #periods
2. #abbreviations
3. #preferable
4. #formal
5. #trouble
6. #lower
7. #these
8. #though
9. #after
10. #popular
11. #writing
12. #capitalize
13. #likely
14. #placed
15. #still