What is the meaning of GSLV Mark 3?

GSLV Mark 3 belongs to the GSLV family of launch vehicles which is the heaviest launch vehicle built by ISRO. You can read about the GSLV Mk III – A Comprehensive Overview of Heavy Lift Launch Vehicle in the given link.

Further readings:

1. Chandrayaan 2 Mission
2. Mars Orbiter Mission (MOM) – Objectives, Payloads