Mogen David vs hexagram

Mogen David and hexagram both are nouns.

Word	Noun	Adjective	Verb	Adverb
Mogen David	Yes	No	No	No
hexagram	Yes	No	No	No

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

Mogen 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 Mogen David include allegory, emblem.

Mogen 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