Postmeridian \Post`me*rid"i*an\, a. [L. postmeridianus; post after + meridianus. See {Meridian}.] 1. Coming after the sun has passed the meridian; being in, or belonging to, the afternoon. (Abbrev. P. M.) [1913 Webster] 2. Fig., belonging to the after portion of life; late. [R.] [1913 Webster]