What is the definition of constellations?
Constellations are really a group of stars that form a fixed patter in the night sky or pictures as the first person said.
A constellation is a group of stars that appear to have a physical proximity in the sky. The stars in a constellation are often vastly distant from each other, but they appear close to each other from the perspective of Earth. The word is used colloquially to refer to asterisms: groups of stars that appear to form patterns in the sky; different world cultures have divided the stars into different constellations. However, in modern astronomy the word refers instead to a method of dividing the sky into 88 areas with exact boundaries.