tailfin vs tail fin

tailfin and tail fin both are nouns.

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

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

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

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

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

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

Other synonyms of tailfin include fin.

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