11-plus vs eleven-plus

11-plus and eleven-plus both are nouns.

Word	Noun	Adjective	Verb	Adverb
11-plus	Yes	No	No	No
eleven-plus	Yes	No	No	No

As nouns, 11-plus and eleven-plus are synonyms defined as:

11-plus and eleven-plus: (formerly in Britain) an examination taken by 11 and 12 year old students to select suitable candidates for grammar school

11-plus (noun)	eleven-plus (noun)
(formerly in Britain) an examination taken by 11 and 12 year old students to select suitable candidates for grammar school	(formerly in Britain) an examination taken by 11 and 12 year old students to select suitable candidates for grammar school