ichidan verb, transitive verb
leave behind; misplace; forget
Used when you put something somewhere and then forget to take it with you, or forget where you put it. The focus is on the act of leaving it unintentionally.
電車に傘を置き忘れてしまった。
I left my umbrella on the train.
どこ
I can't find my keys; I must have misplaced them somewhere.