A shot glass is a small glass designed to hold or measure spirits or liquor

Distilled beverage

A distilled beverage, liquor, or spirit is an alcoholic beverage containing ethanol that is produced by distilling ethanol produced by means of fermenting grain, fruit, or vegetables...

, which is either drunk straight from the glass ("a shot") or poured into a mixed drink

Cocktail

A cocktail is an alcoholic mixed drink that contains two or more ingredients—at least one of the ingredients must be a spirit.Cocktails were originally a mixture of spirits, sugar, water, and bitters. The word has come to mean almost any mixed drink that contains alcohol...

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Shot glasses decorated with a wide variety of humorous pictures, toasts, and advertising, are popular souvenir

Souvenir

A souvenir , memento, keepsake or token of remembrance is an object a person acquires for the memories the owner associates with it. The term souvenir brings to mind the mass-produced kitsch that is the main commodity of souvenir and gift shops in many tourist traps around the world...

s and collectibles

Breweriana

Breweriana commonly refers to any article containing a brewery name or brand name, usually in connection to collecting them as a hobby. Examples include beer cans, bottles, openers, tin signs, coasters, beer trays, wooden cases and neon signs.- History :...

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According to the Oxford English Dictionary

Oxford English Dictionary

The Oxford English Dictionary , published by the Oxford University Press, is the self-styled premier dictionary of the English language. Two fully bound print editions of the OED have been published under its current name, in 1928 and 1989. The first edition was published in twelve volumes , and...

, the term "shot glass" first appeared in print in the 1940s in The New York Times

The New York Times

The New York Times is an American daily newspaper founded and continuously published in New York City since 1851. The New York Times has won 106 Pulitzer Prizes, the most of any news organization...

, but in fact several examples exist from the 1930s, however although it was used by some, the term apparently did not come into common usage until much later.

Many references from the 1800s describe giving a jigger of whiskey or rum to workers who were digging canal

Canal

Canals are man-made channels for water. There are two types of canal:#Waterways: navigable transportation canals used for carrying ships and boats shipping goods and conveying people, further subdivided into two kinds:...

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