One of the five elements of chess, they form the basis of where pieces want to reside, and further dictate where attacks should happen.
A hole is a square that cannot be controlled by your pawns due missing or pushed pawns on both sides of the square. A hole often serves as a dangerous square if the enemy is allowed to occupy it safely with a minor piece. A hole can be defended a maximum of three times by minor pieces (two knights and one bishop), and the attacker generally wants to avoid recapturing on the hole with a pawn and thereby filling it. So it follows that an attacker can only use the hole if they have more minor pieces eyeing it down that the defender.
Term for a plan involving an exchange of pawns in favour of the side with fewer. The idea is to trade in order to create either a backwards pawn or an isolated pawn.
When a player achieves pawns in the center, their plan must try to reinforce them, otherwise they become targets.