Raise or increase, as in The cartel is jacking up oil prices again. This term alludes to the literal meaning of jack up, that is, "hoist with a jack." [Colloquial; c. 1900]
Any player with two pair, where the higher pair are jacks.
SoundPoker Says: In hold'em if your hole cards were J-9, and the community cards included one jack and one 9, you would have two pair, jacks and nines. Or you could exclaim "Jacks Up". Two pair beats one pair.
See Also: Community Cards, Hole Cards, Hooks, Jacks Full, Jaybirds, One Pair, Top Pair, Two Pair