What is a nick?
My son asked me today this odd question: "What is a nick?" His tiny eyes saw my confusion, so he finished: "Like 'nickname.'" The result was a fun lesson in, you guessed it, the laziness of humanity (Isaac will tell you this is a primary concept that I teach).
Well, it started long ago (c. 1300). Originally a “nickname” was an “ekename.” “Eke” means “additional.”(1) How did laziness change it? Around 1550, the phrase “an eke name” had been thoroughly slurred in speech to the point of a kind of phrasal metathesis. A wonderful example of metathesis (2) can be seen in the archaic word “aks” changing to our modern word “ask” (ie., when my dad “aks me a question,” he’s just being archaic, right?).(3)
In a phrase such as what we are discussing, this change is called misdivision(4)—improperly splitting two words or mixing words while still keeping two words. Misdivision is a form of rebrakketicking, and sometimes it is called false splitting. Another famous example comes from the word “napron," which means a “tablecloth” or “napkin." Because "a napron" blends so well with "an apron," the words misdivide and become “an apron”!
Thus... once again, laziness has evolved human communication. One must wonder what kind of changes are coming in the future! Perhaps we should aks a linguist?
(2) "the transposition of sounds or letters in a word"
(4) misdivision, in particular, is often reserved for the case where two words mix but still remain two words—https://en.wikipedia.org/wiki/Rebracketing