1
- a metal bar with a catch and lever used for fastening a door or gate门闩。
1.1
- a spring lock for an outer door, which catches when the door is closed and can only be opened from the outside with a key弹簧锁。
1.2
- Electronics a circuit which retains whatever output state results from a momentary input signal until reset by another signal【电子】门闩线路, 锁存器。
1.3
- the part of a knitting machine needle which closes or opens to hold or release the wool编织机针上的针舌。
with obj.
1- fasten (a door or gate) with a latch闩上（门）：
she latched the door carefully.
她小心地闩上了门。
1.1
- no obj. Electronics (of a device) become fixed in a particular state【电子】（装置）状态恒定。
短语
on the latch
- (of a door or gate) closed but not locked（门）关着但没锁上：
let yourself in, the door's on the latch.
你进来吧, 门没锁。
词源
Old English l æccan 'take hold of， grasp (physically or mentally)'， of Germanic origin.
短语动词
latch on
- (of a breastfeeding baby) manage to get its mouth into the correct position around the nipple（哺乳婴儿）用嘴叼到乳头。
latch on to
informal <非正式>
1
- attach oneself to (someone) as a constant and usually unwelcome companion死皮赖脸地接近（某人）; 纠缠：
he spent the whole evening trying to latch on to my friends.
他整个晚上都纠缠着我的朋友们。
1.1
- take up (an idea or trend) enthusiastically热情地考虑, 热情地接受（想法, 潮流）：
the newspapers latched on to the idea of healthy eating.
报纸热情宣传健康饮食的观念。
1.2
- Brit. (of a football or rugby player) take advantage of (another player's move), typically in order to score a goal or try〈英〉（足球、英橄运动员）利用（另一运动员的行动）：
Nevin latched on to a miscued header to smash home the winning goal.
内文利用一个失误的头球用猛力为本队踢中了那个定胜负的一球。
1.3
- (of one substance) cohere with (another)（一物质）黏附（另一物质）。
2
- understand the meaning of (something)理解, 明白：
with clause she'll soon latch on to what is happening.她很快就会理解发生了什么。