apron string vs apron

apron string and apron both are nouns.

Word	Noun	Adjective	Verb	Adverb
apron string	Yes	No	No	No
apron	Yes	No	No	No

apron string (noun)	apron (noun)
(usually used in the plural) a cord used to tie an apron at the waist	a garment of cloth or leather or plastic that is tied about the waist and worn to protect your clothing
	a paved surface where aircraft stand while not being used
	the part of a modern theater stage between the curtain and the orchestra (i.e., in front of the curtain)
	(golf) the part of the fairway leading onto the green