Wiktionary
drop-down
a. Of a computer menu, opening downward to reveal a list of possible options. alt. Of a computer menu, opening downward to reveal a list of possible options. n. (context computing English) A type of menu that, when selected, opens downward to reveal a list of possible options.
Usage examples of "drop-down".
Lunzie put her things away in the drop-down ceiling locker before she followed Sanborn to the common room to get acquainted with her shipmates.
As the intelligence director spoke, he accessed a drop-down menu of the cities in Botswana.