an appetizer served as a first course at a meal
"The chef decided to serve a shrimp cocktail as the first course of the dinner."
A mixed alcoholic beverage.
"After dinner, we ordered a refreshing cocktail to celebrate our arrival in Paris."
In plain English: A cocktail is an alcoholic drink made by mixing different ingredients together, usually served at parties or bars.
"My friends are having drinks at the bar, and they ordered several different cocktails to celebrate the weekend."
Usage: Use this word to describe a drink made from two or more ingredients combined with ice and garnish. It refers specifically to the final prepared mixture rather than just any combination of liquids.
To adulterate (fuel, etc.) by mixing in other substances.
"The black market gang was arrested after they were caught cocktailing diesel with methanol to evade taxes and increase profits."
In plain English: To cocktail something means to mix it together with other things, usually liquids for drinks.
"The bartender decided to shake up all three ingredients before pouring them into the glass."
Ostentatiously lacking in manners.
"The cocktail's behavior at the dinner party was nothing short of ostentatiously lacking in manners, loudly belching and kicking chairs across the floor."
In plain English: Cocktail describes something that is made by mixing different ingredients together to create a new flavor or effect.
"The cocktail party was filled with people in fancy attire and colorful decorations."
The word cocktail first appeared in the early 17th century from the combination of cock and tail, originally describing a horse with its tail standing up like that of a rooster. While experts do not know exactly how it came to mean an alcoholic mixed drink, one popular theory suggests it referred to a stimulating beverage similar to a pick-me-up.