gold star · noun1
From Gold + star from the star shape of the award and its colour, representing the highest of three levels: gold, silver, bronze.
Gold Star · noun2
From gold + star from the shape of the medal, being star-shaped, and the colouration of the medal, being golden, with gold representing the highest of three grades of star medals, of traditional usage of metallic colours, gold, silver, bronze.
Etymology from Wiktionary, CC BY-SA 4.0.