Drawer

A panel that slides in from the edge of the screen, holding secondary content or navigation.

Drawers typically enter from the left or right edge, sometimes from the top or bottom. They can be modal (block the underlying content with a scrim) or persistent (push the main content aside). Material Design formalizes them as 'side sheets'; iOS uses the pattern in apps like Mail and Messages.

Also called

side sheetside panelnavigation drawer

When to use

Mobile navigation that would crowd the viewport if always visible
Filters or settings that need lots of room but aren't always open
Secondary tools alongside primary content

When not to use

Critical navigation the user needs at-a-glance (use a visible nav bar)
Quick choices a popover or menu would handle better

Bottom sheet Off-canvas Popover

Source

Material Design ('side sheet', 'navigation drawer'). 'Drawer' is the vernacular name.