noun
plural jacks
[count] :a device used for lifting something heavy (such as a car)
[count] :a playing card that has a picture of a soldier or servant and that is worth more than a ten and less than a queen
[count] :a small opening where something connects with a wire to something else
[count] :a small usually metal object that has six points and that is used in the game of jacks
b jacks [plural] :a child's game in which jacks are thrown and picked up while bouncing and catching a small ball
[noncount] US slang :anything at all - used in negative statements
verb
jacks; jacked; jacking
jack in
[phrasal verb]
jack in (something) or jack (something) in Brit informal :to stop doing (something)
jack off
[phrasal verb] US informal + impolite of a man :masturbate
jack up
[phrasal verb]
jack up (something) or jack (something) up
to lift (something, such as a car) with a jack
informal :to increase (something, such as a price) by a large amount