voicemail vs voice mail

voicemail and voice mail both are nouns.

Word	Noun	Adjective	Verb	Adverb
voicemail	Yes	No	No	No
voice mail	Yes	No	No	No

As nouns, voicemail and voice mail are synonyms defined as:

voicemail and voice mail: a computerized system for answering and routing telephone calls; telephone messages can be recorded and stored and relayed

voicemail (noun)	voice mail (noun)
a computerized system for answering and routing telephone calls; telephone messages can be recorded and stored and relayed	a computerized system for answering and routing telephone calls; telephone messages can be recorded and stored and relayed