Trunks lived alone with his mother in a dead future for most of his life…

I can’t tell if I want to or don’t want to know how he found out what a milf is.

Well there is also Trunk's Grandmother to consider.

ithekro said:

Well there is also Trunk's Grandmother to consider.

True. Since Mrs. Briefs is, if I recall, actually cloned over and over again by Mr. Briefs (so he always has a young, hot wife), she'd have been around until Capsule Corp. was destroyed. Trunks would have been quite young then (around two or three, I think, it depends on how long the Androids took to kill off all the remaining Z-fighters and take over.) but he'd still have vague memories.

ithekro said:

Well there is also Trunk's Grandmother to consider.

You’re right. Just seeing her once, even as a baby, would permanently imprint the word onto your mind. Her existence is so linked to the word, he wouldn’t ever need to actually hear the word.