Word Origin & History
abstracted from phrase for þe naness (c.1200) "for a special occasion, for a particular purpose," itself a misdivision of for þan anes "for the one," in reference to a particular occasion or purpose, the þan being from O.E. dative def. article þam. The phrase used from early 14c.
as an empty filler in metrical composition. Hence, nonce-word "word coined for a special occasion," 1954.