Star of David vs hexagram

Star of David and hexagram both are nouns.

Word	Noun	Adjective	Verb	Adverb
Star of David	Yes	No	No	No
hexagram	Yes	No	No	No

As nouns, hexagram is a hypernym of Star of David; that is, hexagram is a word with a broader meaning than Star of David:

Star of David: a six-pointed star formed from two equilateral triangles; an emblem symbolizing Judaism
hexagram: a regular polygon formed by extending each of the sides of a regular hexagon to form two equilateral triangles

Other hypernyms of Star of David include allegory, emblem.

Star of David (noun)	hexagram (noun)
a six-pointed star formed from two equilateral triangles; an emblem symbolizing Judaism	a regular polygon formed by extending each of the sides of a regular hexagon to form two equilateral triangles