Wiktionary
n. Message left on a voice mail system.
Wikipedia
Voice message refers to a message that could be sent to a destination using voice media. Voice itself could be 'packaged' and sent through the IP backbone so that it reaches its marked 'address'. In a technical sense, the process of sending 'voice packets' is a semi passive way of communication. However, given the speed at which it could be delivered can make the communication sound seamless.
Usage examples of "voice message".
You know about how they can strip down a taped voice message-leave out the unnecessary parts of speech, edit out the pauses, even drop some of the useless syllables?
The car's IT facilities were fairly basic, lacking access to a translator, and he was not sure if a human mailbox would store his voice message understandably.
The next few minutes Kirk spent recording his voice message: This is Captain James Kirk, using this method of communication because my primary system has been destroyed.
Ky added the schematics to her voice message and heard a grunt from the other end.