In linguistics, a cranberry morpheme is a bound morpheme that exists in only one lexeme. Examples in English include twi in twilight, and spick and span in spick-and-span.

The canonical example is the cran of cranberry. It is unrelated to the word cran meaning a case of herrings, and though it actually comes from crane (the bird), this is not superficially obvious. Likewise, mul exists only in mulberry (mul is from Latin morus, the mulberry tree). Phonetically, the first morphemes of gooseberry and raspberry also count as cranberry morphemes, as they don't occur by themselves, but the spelling gives a clue to their obscure origins. Compare these to blackberry, which has two obvious unbound morphemes. The first morphemes of loganberry and boysenberry are derived from names.

Cranberry morphemes can arise in several ways:

• A dialect word can become part of the standard language in a compound, but not in its root form: e.g. blatherskite, "one who talks nonsense", has Scots skite meaning "contemptible person".
• A word can become obsolete in its root form but remain current in a compound: e.g. lukewarm from Middle English luke "tepid".
• A compound loanword may have a recognisable native cognate for one element but not the other: e.g. hinterland is from German hinter "behind" and land "land".
• A loanword may have one part misanalysed to a false cognate: e.g. a taffrail is a type of rail, but the word comes from Dutch tafereel "carved panel".

See also

• Morphology