We found 2 dictionaries that define the word drop-down menus:

General (2 matching dictionaries)

1. drop-down menus, drop-down menus: Collins English Dictionary
2. drop-down menus: Cambridge Advanced Learner's Dictionary

(Note: See drop-down_menu as well.)

Definitions from Wiktionary (drop-down menu) ▸ noun:  dropdown list ▸ Also see drop-down_menu ▸ Words similar to drop-down menus ▸ Usage examples for drop-down menus ▸ Idioms related to drop-down menus ▸ Wikipedia articles (New!) ▸ Words that often appear near drop-down menus ▸ Rhymes of drop-down menus ▸ Invented words related to drop-down menus