double shot vs 100 mL

double shot and 100 mL both are nouns.

Word	Noun	Adjective	Verb	Adverb
double shot	Yes	No	No	No
100 mL	Yes	No	No	No

As nouns, double shot and 100 mL are synonyms defined as:

double shot (noun)	100 mL (noun)
100 mL of liquor, drunk from a shot glass.	100 mL of liquor, drunk from a shot glass.