Bootleg has multiple meanings depending on the context. Here are some of the most common definitions:

• Bootleg recording: An audio or video recording of a performance not officially released by the artist or under other legal authority. Making and distributing such recordings is known as bootlegging. The term "bootleg" originates from the practice of smuggling illicit items in the legs of tall boots, particularly the smuggling of alcohol during the American Prohibition era.

• Illicit or unauthorized product: This term has become an umbrella term for illicit, unofficial, or unlicensed recordings, including vinyl LPs, silver CDs, or any other commercially sold media or material.

• Illegal manufacture, sale, or transport of something: To carry (alcoholic liquor) on ones person illegally, to manufacture, sell, or transport for sale (alcoholic liquor) illegally, to produce, reproduce, or distribute illicitly or without authorization, or to smuggle.

• Stolen, smuggled, or pirated: Something that is sold illegally, usually because it was stolen in the first place.

• Remix made without permission from the copyright-holders of the original music: In the context of electronic music, a "bootleg" mix is a remix or mashup that is made without permission from the copyright-holders of the original music.

Its important to note that bootlegs should not be confused with counterfeit or unlicensed recordings, which are merely unauthorized duplicates of officially released recordings, often attempting to resemble the official product as closely as possible.