latch
UK[lætʃ]US[lætʃ]
n
a simple fastening device for a door or gate, consisting of a bar that fits into a notch or slot and is lifted by a lever or string from the other side.
n
a type of lock for a door that locks automatically when the door is closed.
v
to fasten something with a latch.
v
(computing) to maintain an output state even after the input signal changes.
Etymology
the word 'latch' originates from the middle english 'lacchen' or 'lachen', meaning to seize or grasp. this, in turn, derives from the old english 'læccan', which carried the same meaning of catching hold of or seizing. the semantic evolution is clear: from the physical action of grasping, the word came to denote the device that 'catches' or holds a door closed. its journey is purely within the germanic branch, with cognates in other germanic languages, and it is not traceable to a reconstructed proto-indo-european root with certainty.
Analysis
the word 'latch' is a simplex word of germanic origin. it does not break down into smaller, meaningful morphemes within modern english spelling.
Examples
she lifted the latch and pushed the old wooden gate open.
make sure the door latch engages properly when you close it.
the baby latched onto her finger and wouldn't let go.