British Imperial System vs English system

British Imperial System and English system both are nouns.

Word	Noun	Adjective	Verb	Adverb
British Imperial System	Yes	No	No	No
English system	Yes	No	No	No

As nouns, British Imperial System and English system are synonyms defined as:

British Imperial System and English system: a system of weights and measures based on the foot and pound and second and pint

Other synonyms of British Imperial System include British system.

British Imperial System (noun)	English system (noun)
a system of weights and measures based on the foot and pound and second and pint	a system of weights and measures based on the foot and pound and second and pint