The correct spelling of the word is "nothing" /ˈnʌθɪŋ/. It is often misspelled as "not thing," which does not make sense phonetically. "Nothing" has two syllables: "noth" and "ing." The "th" sound in "noth" is pronounced with the tongue between the teeth, while the "ing" sound at the end is pronounced with the tongue at the back of the mouth. It is important to spell words correctly to avoid confusion and convey meaning accurately.
The term "not thing" does not have a specific etymology as it is not a widely recognized word or phrase. "Not thing" is simply a combination of the word "not", which negates or denies something, and the term "thing", referring to an object or entity. It is possible that the expression is used colloquially or in certain contexts to emphasize the absence or negation of a particular thing, but it does not have a distinct historical or linguistic origin.