reef knot vs square knot

reef knot and square knot both are nouns.

Word	Noun	Adjective	Verb	Adverb
reef knot	Yes	No	No	No
square knot	Yes	No	No	No

As nouns, square knot is a hypernym of reef knot; that is, square knot is a word with a broader meaning than reef knot:

reef knot: a square knot used in a reef line
square knot: a double knot made of two half hitches and used to join the ends of two cords

reef knot (noun)	square knot (noun)
a square knot used in a reef line	a double knot made of two half hitches and used to join the ends of two cords