ruler vs metrestick

ruler and metrestick both are nouns.

Word	Noun	Adjective	Verb	Adverb
ruler	Yes	No	No	No
metrestick	Yes	No	No	No

As nouns, metrestick is a hyponym of ruler; that is, metrestick is a word with a more specific, narrower meaning than ruler:

ruler: measuring stick consisting of a strip of wood or metal or plastic with a straight edge that is used for drawing straight lines and measuring lengths
metrestick: a rule one meter long (usually marked off in centimeters and millimeters)

Other hyponyms of ruler include carpenter's rule, foot rule, meterstick, yard measure, yardstick.

ruler (noun)	metrestick (noun)
measuring stick consisting of a strip of wood or metal or plastic with a straight edge that is used for drawing straight lines and measuring lengths	a rule one meter long (usually marked off in centimeters and millimeters)
a person who rules or commands