spring onion vs scallion

spring onion and scallion both are nouns.

Word	Noun	Adjective	Verb	Adverb
spring onion	Yes	No	No	No
scallion	Yes	No	No	No

As nouns, spring onion and scallion are synonyms defined as:

spring onion and scallion: a young onion before the bulb has enlarged; eaten in salads

Other synonyms of spring onion include green onion.

spring onion (noun)	scallion (noun)
a young onion before the bulb has enlarged; eaten in salads	a young onion before the bulb has enlarged; eaten in salads
	plant having a large slender white bulb and flat overlapping dark green leaves; used in cooking; believed derived from the wild Allium ampeloprasum