Question

what is galaxy define briefly​

Answer 1

A galaxy is a huge collection of gas, dust, and billions of stars and their solar systems. A galaxy is held together by gravity. Our galaxy, the Milky Way, also has a supermassive black hole in the middle. When you look up at stars in the night sky, you're seeing other stars in the Milky Way.

Answer 2

$\large{A  \: galaxy  \: is \: a \: huge \: collection \: of \:} \\ \large{gas, \: dust, \: and \: billions \: of \: stars }\\ \large{and \: their \: solar \: systems. }\\ \large{A \:  galaxy \:  is \: held \: together \: by} \\ \large{ gravity. Our  \: galaxy, \: the \: Milky Way, }\\ \large{also \: has \: a \: supermassive }\\ \large{ black \: hole \: in \: the \: middle. \: When }\\ \large{you \: look \: up \: at \: stars \: in \: the \: night} \\ \large{ sky, \: you're \: seeing \: other \: stars \: in} \\ \large{the \: Milky \: Way.}$