On the rocks

Various unique terminology is used in bartending.

In bartending, the term "straight up" (or "up") refers to an alcoholic drink that is shaken or stirred with ice and then strained and served without ice in a stemmed glass.

This is contrasted with a drink served "neat" – a single, unmixed liquor served without being chilled and without any water, ice, or other mixer. Neat drinks are typically served in a rocks glass, shot glass, snifter, Glencairn glass, or copita.

"On the rocks" refers to liquor poured over ice cubes, and a "rocks drink" is a drink served on the rocks. Rocks drinks are typically served in a rocks glass, highball glass, or Collins glass, all of which refer to a relatively straight-walled, flat-bottomed glass; the rocks glass is typically the shortest and widest, followed by the highball which is taller and often narrower, then the Collins which is taller and narrower still.

The terms "straight" and "straight up" can be ambiguous, as they are sometimes used to mean "neat"; "up" is less ambiguous.

Drinks establishments will often have a lower-priced category of drinks, known as "well drinks" or "rail drinks", and a higher-priced category known as "top-shelf" or "call" drinks, and will use upselling by offering the higher-priced category when taking orders. The terms come from the relative positions of the bottles of spirit used for the drinks; the cheapest version of a spirit offered by a bar is typically stored in a long rail or "well" making it readily available to a busy bartender, while the more expensive, better-quality liqueurs and spirits are stored on shelves behind the bar where they attract patrons to the available selection.

A "" is slang for one US fluid ounce (30 ml) of spirit, while the standard-size "shot" of alcohol is a 1.5-US-fluid-ounce (44 ml) "jigger", with a "double" being three US fluid ounces (89 ml).

...
Wikipedia