purse string vs drawstring

purse string and drawstring both are nouns.

Word	Noun	Adjective	Verb	Adverb
purse string	Yes	No	No	No
drawstring	Yes	No	No	No

As nouns, drawstring is a hypernym of purse string; that is, drawstring is a word with a broader meaning than purse string:

purse string: a drawstring used to close the mouth of a purse
drawstring: a tie consisting of a cord that goes through a seam around an opening

Other hypernyms of purse string include drawing string, string.

purse string (noun)	drawstring (noun)
a drawstring used to close the mouth of a purse	a tie consisting of a cord that goes through a seam around an opening