afterthought

nouns

thinking again about a choice previously made
"he had second thoughts about his purchase"
afterthought, reconsideration, rethink, second thought
an addition that was not included in the original plan
"the garage was an afterthought"
afterthought
is a type of (narrower)
a component that is added to something to improve it
"the addition of a bathroom was a major improvement"; "the addition of cinnamon improved the flavor"
add-on, addition, improver