drop-down

/D R AA1 P D AW1 N/
noun
  1. 1

    An instance of a selection object that hides the contents (especially the other choices) until activated.

    โ€œThat screen is good, but add a couple of dropdowns and it will be perfect.โ€

adjective
  1. 1

    (of a widget) Dropping down from above; being a specific type of selection control that hides its contents until activated.

    โ€œClick the Colours button on the toolbar to show a dropdown menu of available colours.โ€

Source: https://en.wiktionary.org/wiki/drop-down, https://en.wiktionary.org/wiki/dropdown