buy in

Short definition from Wiktionary

Noun

1. 1
   Misspelling of buy-in.
2. 2
   Support; agreement; blessing (in a secular sense).
3. 3
   A tournament where a player must purchase all of his or her chips before the tournament starts.
4. 4
   The amount that a player buys in for

Verb

1. 1
   To accept an idea as valid; to join in on a concept.
2. 2
   To invest as part of a group; to put one's personal stake in an investment.
3. 3
   To buy back for the owner at an auction.
4. 4
   For the buyer of securities, whose seller fails to deliver the securities contracted for, to buy the securities from a third party and demand the difference in price from the original seller.