Latch

This latch can be opened from outside the door or from inside.

A latch is used to close a farm gate, but is also easy to open.

A lock and two latches on a trunk

This window latch can hold the window open or hold it closed.

A latch is a type of hardware that is used to join two objects together. A latch often keeps animals or wind from opening something. This could be a door or a gate. Unlike a lock, a latch is easy to open if you know how, so it can be convenient on a gate that needs to be opened often.

a childproof latch (also called a baby latch) is designed to keep children from opening doors or drawers. They keep children from getting into things such as household cleaners, medicines, matches or knives.^[1]
a gate latch is used for outdoor gates. There are a wide variety of types. There are also a number of considerations before choosing a gate latch.^[2]
a Touch latch holds a door in the closed position. It releases with a gentle touch on the door.^[3]

Latch Media

Opening a captured draw bolt-style latch
Knob has crescent-shaped bar which pulls back latch bolt when turned. Version on upper right has a lock; version on upper left does not. Kwikset uses this shape. Other companies have square or D-shaped bars.
Electronic cam lock
Comparison of Suffolk and Norfolk latches.
HenriettaS.Hukill,NorfolkLatch,c.,NGA
A wooden crossbar on a door
An aldrop latch, a form of draw bolt
Latch (en:Latch), painted with Falu red (en:Falu red)
Close-up of springform pan