Definition of crai
Crai stands for Check Raise All In. This is its abbreviation. Obviously, you will not hear anyone say in a casino "the player was crai". Rather, it is a shorthand for writing a hand. For example: BTN bets 50, SB raises to 150 (crai). We then know that BTN will have to call 100 in total if he wants to continue in the hand.
Some other poker abbreviations
If you study poker hands a lot, you will see a lot of these abbreviations. Most trackers are in English, so the abbreviations will always refer to English words. Here is a non-exhaustive list of these abbreviations: Continuation bet (cb), check/raise (c/r), check/fold (c/f), Under The Gun (UTG), Middle Position (MP), Hijack (HJ), Low Jack (LJ), Cutoff (CO), Button (BTN), Small Blind (SB), Big Blind (BB), Three Bet (3b), Four Bet (4b), Preflop Raise (PFR), Voluntary Put Money Into Pot (VPIP), Donk bet (DB), Check/Raise (c/r or x/r).