tail fin vs tailfin

tail fin and tailfin both are nouns.

Word	Noun	Adjective	Verb	Adverb
tail fin	Yes	No	No	No
tailfin	Yes	No	No	No

As nouns, tail fin and tailfin are synonyms defined as:

tail fin and tailfin: a stabilizer that is part of the vertical tail structure of an airplane

Other synonyms of tail fin include vertical fin, vertical stabiliser, vertical stabilizer.

As nouns, tail fin and tailfin are synonyms defined as:

tail fin and tailfin: one of a pair of decorations projecting above the rear fenders of an automobile

Other synonyms of tail fin include fin.

tail fin (noun)	tailfin (noun)
the tail of fishes and some other aquatic vertebrates	a stabilizer that is part of the vertical tail structure of an airplane
a stabilizer that is part of the vertical tail structure of an airplane	one of a pair of decorations projecting above the rear fenders of an automobile
one of a pair of decorations projecting above the rear fenders of an automobile