Bottom Pair
In poker, the term “bottom pair” is usually used to describe a situation where one of your cards matches one of the community cards on the board, and this pair is the lowest-ranking of the possible pairs.
For example, if you have a 5 and a 9 in your hand, and on the board there’s a 5, a 10, a king, a 7, and a 2, then you’ll have a “bottom pair” of fives, because that’s the lowest-ranking pair you can make using the cards on the board.