field glasses vs binoculars

field glasses and binoculars both are nouns.

Word	Noun	Adjective	Verb	Adverb
field glasses	Yes	No	No	No
binoculars	Yes	No	No	No

As nouns, field glasses and binoculars are synonyms defined as:

field glasses and binoculars: (plural) an optical instrument designed for simultaneous use by both eyes

Other synonyms of field glasses include opera glasses.

field glasses (noun)	binoculars (noun)
(plural) an optical instrument designed for simultaneous use by both eyes	(plural) an optical instrument designed for simultaneous use by both eyes