In Go, a liberty is an empty adjacent intersection that gives a stone or group of stones a 'breathing space'. A stone without liberties is captured.
When all the liberties of a stone are filled, that stone is captured.
Beginners should start by practicing counting the number of liberties.
Compound of 呼吸 (breathing) and 点 (point), literally 'breathing point'. The term describes the empty points that give a stone 'life' in the game of Go.