Question

what is galaxy,one line definition required, in which galaxy we live

Answer 1

hai friend,

here is your answer,

galaxy is a collection of stars

our galaxy is milky way

or

A galaxy is a gravitationally bound system of stars, stellar remnants,interstellar gas, dust, and dark matter.
hope helped

Answer 2

All the group of stars in the sky is known as constellation,all constellation in group is known as galaxy..