size stick vs measuring rod

size stick and measuring rod both are nouns.

Word	Noun	Adjective	Verb	Adverb
size stick	Yes	No	No	No
measuring rod	Yes	No	No	No

As nouns, measuring rod is a hypernym of size stick; that is, measuring rod is a word with a broader meaning than size stick:

size stick: a mechanical measuring stick used by shoe fitters to measure the length and width of your foot
measuring rod: measuring instrument having a sequence of marks at regular intervals; used as a reference in making measurements

Other hypernyms of size stick include measure, measuring stick.

size stick (noun)	measuring rod (noun)
a mechanical measuring stick used by shoe fitters to measure the length and width of your foot	measuring instrument having a sequence of marks at regular intervals; used as a reference in making measurements