The term ‘Big Pairs’ refers to the pre-flop starting hand in Texas Hold’em, which are the two hole cards that are dealt to each player.
A big pair is generally considered any pair higher than 10-10. This means big pairs represent J-J, Q-Q, K-K and A-A. These are also known as premium starting hands as they represent the greatest chances of winning with the hand pre-flop.
As with most things in life, this can quickly change and whilst these might be very strong before the flop is dealt, they are very easily beaten on the flop. Even pocket aces will win about 80% of the time against one other player.