Up The Ante Meaning

Example :   With three aces and two jacks, he thought it was safe to up the ante.  The school system cannot raise teachers' salaries, so they are providing better benefits as an effort to up the ante.2011 November 3, Chris Bevan, “Rubin Kazan 1 - 0 Tottenham”[1], BBC Sport:  After a slow start, it was the home side who began to up the ante. Gokdeniz Karadeniz caused Spurs problems with his raids down the right and Alan Kasaev fired narrowly over from one of his pull-backs.