Astronomical Term for the Brightness of a Star

This page is the CodyCross answer for the clue below from Treasure Island, Group 1033, Puzzle 2 (Stolen Goods).

Question is: Astronomical Term for the Brightness of a Star

and the answer is: MAGNITUDE

Word Meaning:

MAGNITUDE — (uncountable, countable) The absolute or relative size, extent or importance of something.

Definitions from Wiktionary.