Definition of proof spirit
: an alcoholic liquor or mixture of ethanol and water that contains 50 percent ethanol by volume at 60°F (16°C)
First Known Use of proof spirit
Medical Definition of proof spirit
1: an alcoholic liquor or mixture of alcohol and water containing 50 percent ethanol by volume at 60° F (15.6°C)
2British : liquor that weighs 12⁄13 of an equal measure of distilled water or contains 57.10 percent by volume of alcohol
Seen and Heard
What made you want to look up proof spirit? Please tell us where you read or heard it (including the quote, if possible).