chalk line vs snap line

chalk line and snap line both are nouns.

Word	Noun	Adjective	Verb	Adverb
chalk line	Yes	No	No	No
snap line	Yes	No	No	No

As nouns, chalk line and snap line are synonyms defined as:

chalk line and snap line: a chalked string used in the building trades to make a straight line on a vertical surface

Other synonyms of chalk line include snapline.

chalk line (noun)	snap line (noun)
a chalked string used in the building trades to make a straight line on a vertical surface	a chalked string used in the building trades to make a straight line on a vertical surface