latch

[lach] /lætʃ/
noun
1.
a device for holding a door, gate, or the like, closed, consisting basically of a bar falling or sliding into a catch, groove, hole, etc.
verb (used with object)
2.
to close or fasten with a latch.
verb (used without object)
3.
to close tightly so that the latch is secured:
The door won't latch.
Verb phrases
4.
latch on,
  1. to grab or hold on, as to an object or idea, especially tightly or tenaciously.
  2. to include or add in; attach:
    If we latch the tax on, the bill will come to over $100.
5.
latch onto, Informal.
  1. to take possession of; obtain; get.
  2. to acquire understanding of; comprehend.
  3. to attach oneself to; join in with:
    The stray dog latched onto the children and wouldn't go home.
Origin
before 950; 1930-35 for def 5; Middle English lacchen, Old English lǣccan to take hold of, catch, seize; akin to Greek lázesthai to take
Related forms
relatch, verb (used with object)
Examples from the web for latch
  • Many parents, determined not to be cruel or counterproductive, latch on to pre-approved language from books.
  • Primed for triumph, they were ready to latch onto a symbol of what they believed would be a joyous finale to the war.
  • Often something pops up in the conclusion that you can latch onto.
  • All it would take is for a single spore, barely bigger than a red blood cell, to latch onto the shirt of an oblivious traveler.
  • As the industry struggles, people will latch onto mainstream comic books.
  • There should be a place on the case to affix a latch to close the case.
  • Every backyard pool was given a gate with a childproof latch.
  • If they see you are going to be successful, they latch on to you.
  • He couldn't get the suitcase-sized experiment to latch firmly onto the platform.
  • First her eyes latch onto mine, then her head swings around in a mechanical two-step.
British Dictionary definitions for latch

latch

/lætʃ/
noun
1.
a fastening for a gate or door that consists of a bar that may be slid or lowered into a groove, hole, etc
2.
a spring-loaded door lock that can be opened by a key from outside
3.
(electronics) Also called latch circuit. a logic circuit that transfers the input states to the output states when signalled, the output thereafter remaining insensitive to changes in input status until signalled again
verb
4.
to fasten, fit, or be fitted with or as if with a latch
Word Origin
Old English læccan to seize, of Germanic origin; related to Greek lazesthai
Word Origin and History for latch
v.

Old English læccan "to grasp or seize," from Proto-Germanic *lakkijanan. Not found in other Germanic languages; probably from PIE *(s)lagw- "to seize" (see analemma). In its original sense the verb was paralleled in Middle English and then replaced by French import catch (v.). Meaning "to fasten with a latch" is mid-15c. Related: Latched; latching.

n.

a fastening for a door, etc., late 13c., probably from latch (v.).

latch in Technology


A digital logic circuit used to store one or more bits. A latch has a data input, a clock input and an output. When the clock input is active, data on the input is "latched" or stored and transfered to the output either immediately or when the clock input goes inactive. The output will then retain its value until the clock goes active again.
See also flip-flop.
(1995-02-03)