olemus
tõkestav element otseses või ülekantud tähenduses

Wiktionary:
1. a fastening for a door that has a bar that fits into a notch or slot, and is lifted by a lever or string from either side
7. (databases) a lightweight lock to protect internal structures from being modified by multiple concurrent accesses

ülevaateid
https://en.wikipedia.org/wiki/Latch

https://www.iqsdirectory.com/articles/latch.html

näiteid
https://duckduckgo.com/?q=latch&t=h_&iax=images&ia=images