English word nonmethane comes from English methane, English non-
| Dictionary entry | Language | Definition |
|---|---|---|
| methane | English (eng) | (organic chemistry, countable) Any of very many derivatives of methane.. (organic compound, uncountable) The simplest aliphatic hydrocarbon, CH4, being a constituent of natural gas. |
| non- | English (eng) | Used in the sense of not, to negate the meaning of the word to which it is prefixed. |
| nonmethane | English (eng) | Not methane. |