Not as common as postprandial, of or taking place after dinner. Coined in the 1810s from Latin prandium, a late breakfast or luncheon, which Lewis & Short tells me would be taken around noon, consisting of bread, fish, or cold meats, and comes from pra-, before + dies, day -- so breakfast for late risers. (How this got generalized to any meal, no one seems to go into.) Compare to jentacular, of or relating to breakfast early in the morning, from Latin ientaculum, a breakfast taken immediately on getting up.
And so we relearned the lost art of prandial conversation.