Neologism

A neologism is a word or phrase that has been coined to cover a specific need. New words and expressions are constantly entering the language and while modern technologies allow for dictionaries to be updated more frequently than in the past, neologisms are often in widespread use long before becoming accepted "officially".

Typical examples include radar (more specifically an acronym), blog (more specifically a portmanteau), googling, Orwellian, among many others.

Though most frequently used as a noun, "a newly coined word or expression", or as a mass noun, "the coining or use of new words", the verb "neologize" (or "neologise") also exists.

Of course, once it's been in use for a while, a neologism ceases to be a neologism.