Spirits are best served:
Neat - Directly poured into a glass.
Up - Refers to serving a spirit chilled. Combined with ice, shaken, strained, and served without the ice.
Straight Up - Refers to mixed drinks or cocktails, such as martinis and manhattans. Combined with ice, shaken, strained, and served without the ice.
Straight - Sometimes used interchangeably with “neat” when the appropriate term is “straight” for a particular type of spirit.
On The Rocks - Poured and served with ice cubes.