Wiktionary
n. A vote that is held by members calling out aye or nay, used in cases where result is not contested or at least not close and a count is not needed to determine if the motion passes.
Wikipedia
In parliamentary procedure, a voice vote (or viva voce, from the Latin, "live voice") is a voting method in deliberative assemblies (such as legislatures) in which a vote is taken on a topic or motion by responding verbally.
The voice vote, or acclamation, is considered the simplest and quickest of voting methods used by deliberative assemblies. The presiding officer or chair of the assembly will put the question to the assembly, asking first for all those in favor of the motion to indicate so verbally ("aye" or "yes"), and then ask second all those opposed to the motion to indicate so verbally ("nay" or "no"). The chair will then make an estimate of the count on each side and state what he or she believes the result to be. Since in close cases this can be imprecise, typically if there is any doubt as to the outcome any member of the assembly may request another vote by a method such as division of the assembly (a standing or rising vote), or a roll call vote. Voice votes are usually not recorded, while others are.