From Longman Dictionary of Contemporary Englishafterthoughtaf‧ter‧thought /ˈɑːftəθɔːt $ ˈæftərθɒːt/ noun [countable] AFTERsomething that you mention or add later because you did not think of it or plan it before He added as an afterthought, ‘Bring Melanie too.'
Examples from the Corpus
afterthought• I was frisked, my belt and Seiko taken from me, and, as an afterthought, kicked in the ribs.• Too late and the greeting is grunted as an afterthought as you both pass only feet away from each other.• He offered it to Coffin, not as a prize, but more as an afterthought.• The tiles looked out of place, as if they had been an afterthought.• Having said good-bye, he had paused as if in an afterthought.• All too often, lighting is an afterthought superimposed on the final decoration instead of being planned from the start.• In her editorial Vivienne Van Someren suggests that arrangements for job sharers are often an afterthought.• In Mission Valley, housing was an afterthought. 