The creature that is half-human and half-horse in Greek mythology is the centaur.
A centaur has the upper body of a human attached to the body and legs of a horse. Greek myths place centaurs especially in Thessaly, including Magnesia and Mount Pelion, as well as other wooded and mountainous regions. They are often portrayed as wild, powerful, lustful beings caught between civilized human life and untamed nature.
Their best-known conflict is the Centauromachy, a battle between centaurs and the Lapiths. According to the myth, centaurs attempted to carry off Lapith women during the wedding of Hippodamia and Pirithous. The struggle became a major artistic theme, including on the metopes of the Parthenon.
Not every centaur is savage. Chiron, the most famous exception, was renowned for wisdom, medicine, and teaching heroes such as Achilles and Asclepius. Centaurs are commonly confused with satyrs or fauns, but those beings are usually human-goat hybrids; the Minotaur is human-bull, not human-horse.