bytt is a word with multiple meanings across different languages, most prominently in Swedish.
Swedish
In Swedish, bytt is the past participle and supine form of the verb byta ("to change, swap, exchange"). As an adjective, it means "changed" or "swapped." It appears in the common Swedish proverb Bytt är bytt och kommer aldrig igen ("What is swapped is swapped and will never come back"), which conveys that a completed exchange or deal is final and cannot be undone — analogous to the English saying "no takebacks" or "a deal is a deal."
The phrase Bytt är bytt is also the title of a Swedish television entertainment program that premiered on TV4 on 25 September 2014, hosted by Renée Nyberg. In the show, contestants are presented with eight antique objects of varying values (from 500 SEK to 500,000 SEK) and must eliminate them one by one, ultimately winning the value of the last remaining object.
Cornish
In Cornish, bytt (borrowed from English bit) is a masculine noun meaning "bit" in the computing sense. Its plural form is byttys.
Middle English
In Late Middle English, bytt is an alternative spelling of bite.
Old English
In Old English, bytt is an alternative form of byt, meaning a container or vessel (related to "butt" as in a cask or barrel).
As an acronym (BYT)
In internet slang, the uppercase abbreviation BYT commonly stands for "Before Your Time," used to indicate that something predates the recipient's experience or knowledge.
