A snowball is a ball of snow, usually created by scooping snow with the hands and compacting it into a roughly fist-sized ball. The snowball is necessary to hold a snowball fight.

Other uses of the word snowball include:

• Snowball programming language (computing)
• Snowball Sample A social research sampling method.
• Snowball, a character in George Orwell's political satire Animal Farm.
• Snowball, a feline character in The Simpsons.
• Snowball Earth to refer to periods in which nearly the entire planet was glaciated.
• Snowballing: (Slang) A sexual practice in which semen is transferred, orally, into the mouth of a person who has just been fellated. This transfer is usually via a French kiss. See also fellatio.
• The nickname of the character William Black from Kevin Smith's Clerks and Mallrats movies. The name refers to the aforementioned sexual practice.
• A cocktail, briefly fashionable in the 1970s, made of about one part of Advocaat (a Dutch brand of egg nog) and eight parts of lemonade, usually served with ice and a slice of lemon.
• A regional treat made of shaved ice and flavorings popular in Baltimore, Maryland.
• A situation, event or the like is said to snowball if it continually grows in intensity or magnitude. This is a reference to the way snowballs get bigger gradually by picking up more snow when one rolls them around or down a hill.
• A surname, originating from a man with a white patch of hair on his head