Rebracketing (also known as resegmentation or metanalysis) is a process in historical linguistics where a word originally derived from one set of morphemes is broken down or bracketed into a different set. For example, hamburger, originally from Hamburg+er, has been rebracketed into ham+burger, and burger was later reused as a productive morpheme in coinages such as cheeseburger. It is usually a form of folk etymology, or may seem to be the result of valid morphological processes.

Rebracketing often focuses on highly probable word boundaries: "a noodle" might become "an oodle", since "an oodle" sounds just as grammatically correct as "a noodle", and likewise "an eagle" might become "a neagle", but "the bowl" would not become "th ebowl" and "a kite" would not become "ak ite".

Technically, bracketing is the process of breaking an utterance into its constituent parts. The term is akin to parsing for larger sentences, but it is normally restricted to morphological processes at the sublexical level, i.e. within the particular word or lexeme. For example, the word uneventful is conventionally bracketed as [un+[event+ful]], and the bracketing [[un+event]+ful] leads to completely different semantics. Re-bracketing is the process of seeing the same word as a different morphological decomposition, especially where the new etymology becomes the conventional norm. The name false splitting, also called misdivision, in particular is often reserved for the case where two words mix but still remain two words (as in the "noodle" and "eagle" examples above).

The name juncture loss may be specially deployed to refer to the case of an article and a noun fusing (such as if "the jar" were to become "(the) thejar" or "an apple" were to become "(an) anapple"). Loss of juncture is especially common in the cases of loanwords and loan phrases in which the recipient language's speakers at the time of the word's introduction did not realize an article to be already present (e.g. numerous Arabic-derived words beginning 'al-' ('the'), including "algorithm", "alcohol", "alchemy", etc.). Especially in the case of loan phrases, juncture loss may be recognized as substandard even when widespread; e.g. "the hoi polloi", where Greek hoi = "the", and "the Magna Carta", in which no article is necessary because magna carta is borrowed rather than calqued (Latin's lack of articles makes the original term either implicitly definite or indeterminate with respect to definiteness [in this context, the former], and the English phrase's proper-noun status renders unnecessary any further determination through the use of an article).

As a statistical change within a language within any century, rebracketing is a very weak statistical phenomenon. Even during phonetic template shifts, it is at best only probable that 0.1% of the vocabulary may be rebracketed in any given century.

Rebracketing is part of the process of language change, and often operates together with sound changes that facilitate the new etymology.

Rebracketing is sometimes used for jocular purposes, for example psychotherapist can be rebracketed jocularly as Psycho the rapist, and together in trouble can be rebracketed jocularly as to get her in trouble.