What was the name of the battle where Caesar defeated Pompey in 48 BC?

Caesar defeated Pompey at the Battle of Pharsalus in 48 BC. The battle was the decisive clash of Caesar's Civil War and destroyed Pompey's hopes of defeating his former ally in Greece.

Caesar's army was smaller and had recently suffered a setback at Dyrrachium, but his veteran legions were highly experienced. Pompey commanded a larger force, including a powerful cavalry contingent. Caesar anticipated that Pompey's cavalry would try to envelop his weaker flank, so he held back a reserve of infantry to counter the maneuver. That reserve helped turn the battle in Caesar's favor.

Pompey fled after the defeat and eventually sought refuge in Egypt. Egyptian officials murdered him before Caesar arrived in Alexandria. This is why Pharsalus is sometimes confused with later battles: Caesar also fought at Thapsus and Munda, but those victories came against other Pompeian forces in 46 and 45 BC.