Cards.to make an overcall.
1. Cards.a bid higher than the previous bid.
2. Bridge.a bid on a higher level than, or in a higher ranking suit than, the previous bid of an opponent that was not followed by a bid or double by one's partner.
3. Theater.a clause in an investor's agreement whereby the backer agrees to supply an additional amount of money, often 10 to 20 percent of the original amount, should it be required by the producers.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.