White elephants symbolize something that is more of a burden to its owner than it is worth. The term likely originates from white elephants of Thailand, which were often given as gifts because they were too expensive for their owners to maintain.
In the West, the term "white elephant" is often used to refer to an item that an owner no longer wants. The item is not necessarily worn out or trash; it has simply become more of a hassle than the owner believes it is worth or no longer has a purpose to the owner. White elephants are sometimes given as gifts or are auctioned to those who may have a use for them.
Historically, white elephants in Thailand were given away because they could not be used for the purpose of labor, which detracted from the owner's income. White elephants were sometimes given as gifts to adversaries of Thai royalty, though white elephants in general were and still are a symbol of royalty as of 2014. White elephants have been used as symbolism in literature, most notably in the short story "Hills like White Elephants" by Ernest Hemingway where the main plot line revolves around the decision of an unwanted pregnancy.