Combo box

A combo box is a commonly-used graphical user interface widget. It is a combination of a drop-down list or list box and a single-line textbox, allowing the user to either type a value directly into the control or choose from the list of existing options.

Combo boxes are typically applied to provide autocomplete or autotype functionality in a convenient way to the user.

Terminology
The term "combo box" is sometimes, incorrectly, used to mean "drop-down list". This distinction between "combo box" and "drop down list" is sometimes clarified with terms such as "non-editable combo box" (or something similar).