latch
[noun]
Synonyms:
- fastening, bar, bolt, catch, hasp, hook, lock
[verb]
Synonyms:
- fasten, bar, bolt, make fast, secure

[TahlilGaran] English Synonym Dictionary ▲

I. latch¹ /lætʃ/ noun [countable]

1. a small metal or plastic object used to keep a door, gate, or window closed:
Gwen lifted the latch and opened the gate.

2. especially British English a type of lock for a door that you can open from the inside by turning a handle, but that you need a key to open from the outside
on the latch (=shut but not locked)
Ray went out, leaving the door on the latch.

[TahlilGaran] Dictionary of Contemporary English ▲

II. latch² verb [transitive]
[Language: Old English; Origin: læccan]
to fasten a door, gate, or window with a latch
latch on phrasal verb
British English informal to understand:
He’s so thick it took him ages to latch on.
latch onto somebody/something (also latch on to somebody/something) phrasal verb informal

1. to become very interested in something:
Don’t just latch on to the latest management fads.

2. to follow someone and keep trying to talk to them, get their attention etc, especially when they would prefer to be left alone:
He latched onto Sandy at the party and wouldn’t go away.

3. to hold tightly to something with your hand, mouth etc:
a baby latching on to its mother’s breast

[TahlilGaran] Dictionary of Contemporary English ▲