An antonym for the postmeridian- meaning a time pertaining to the afternoon, is premeridian- which means time relative to the morning. Although, in simplistic terms, saying an antonym for postmeridian is 'morning/time before noon' will suffice.
postmeridian
Sure! "The meeting is scheduled for 3:00 PM postmeridian."
Postmeridian is when something happens or falls after midday. A good sentence would be, he takes his bath postmeridian and brushes teeth in the morning.
Postmeridian is a word meaning something to do with the afternoon or evening. The opposite of this would be antemeridian. For example, the evening paper could be a postmeridian edition.
It is postmeridian at 12:00 pm. or the afternoon.
postmeridian
Wonker.com
Post meridian just simply means after noon. An example sentence would be: She likes to eat her lunch post meridian.
antemeridian is AM; postmeridian is PM.
anti meridian
The antonym of the word 'synonym' is 'antonym'.
An antonym means "opposite". So an antonym for the word synonym is antonym.