The term "ringer" has multiple meanings depending on the context. Here are some of the most common definitions:

• In sports: A ringer is an impostor, especially one whose pretense is intended to gain an advantage in a competition. In horseshoes, a ringer is a shoe that encircles the stake.

• In contests: A ringer is a contestant who lies about their experience or qualifications.

• In general: A ringer can refer to a person or thing that rings or makes a ringing noise, such as a bell. It can also refer to a style of T-shirt.

Other meanings of "ringer" include:

• In medicine: Lactated Ringers solution, also known as Ringers, is a fluid used in medical treatment. Intravenous sugar solution, usually glucose, is also sometimes referred to as a "ringer".

• In entertainment: Ringer is a 2011 TV series starring Sarah Michelle Gellar. It is also the name of a 1996 film starring Timothy Bottoms. Ringer (EP) is an EP by Four Tet, and "Ringer" is a song by Godflesh. Ringer (comics) is a Marvel Comics villain. Ringers: Lord of the Fans is a documentary about Tolkien fandom.

In summary, "ringer" can refer to a person or thing that rings, a contestant who lies about their experience, a horseshoe that encircles the stake, a style of T-shirt, and various other things depending on the context.