What is the definition of scotch glass?

There's no single "scotch glass" in the sense of a specific glass type with that name. However, there are several types of glasses that are commonly used for serving Scotch whisky, each with its own characteristics:

* Glencairn glass: The most popular choice for Scotch whisky, this glass is designed to concentrate aromas and flavors, offering a wide bowl that tapers at the top to direct the whisky to the palate.

* Tumbler: A classic and versatile glass, a tumbler is a wide, low glass that can be used for various beverages, including Scotch. It allows for plenty of ice and mixers.

* Rocks glass: Also known as an Old Fashioned glass, this glass is similar to a tumbler but typically has a slightly thicker base and a wider bowl.

* Snifter: A bulbous glass with a narrow opening, the snifter is designed to concentrate aromas and allows for swirling the whisky to release its flavors. It's best suited for aged and complex Scotch whiskies.

* Copita glass: A stemmed glass with a wide bowl and a narrow opening, the copita is similar to a wine glass but is designed for sipping rather than swirling. It's a less common choice for Scotch.

Ultimately, the best glass for Scotch whisky depends on personal preference and the specific whisky being enjoyed. Some factors to consider include the age, complexity, and flavor profile of the whisky.