What does constellation mean?

Constellation is taken from the Latin con(derivation of "com") which means together and the Latin word stella which means star,so Con-Stella-tion,just means "Stars Together"

In modern astronomical usage, a constellation is a defined patch of sky. There are 88 of these, each with a Latin name.

Sometimes laypeople say "constellation" when they mean "a pattern of stars", but this is technically an asterism (from the Greek word for "star"). The Big Dipper (aka the Plough/the Wain) is probably the most widely recognized asterism; it's in the constellation Ursa Major.