Thio

Part of speech: adjective, noun

Definitions

1. A chemical prefix denoting the presence of sulfur in a compound, typically used in scientific nomenclature
2. Referring to derivatives or compounds that include sulfur in their molecular structure, commonly in organic chemistry
3. An element in molecular terminology indicating the inclusion of sulfur within a compound's structure, especially in chemistry contexts

Etymology: Ancient Greeks called sulfur "theion," and modern chemists took its opening sound as a prefix, "thio-." In names, it marks a compound where a sulfur atom has taken the place of an oxygen atom, so a thio compound is often the sulfur counterpart of a familiar oxygen-based one. The prefix is a modern construction, not something the Greeks used. Chemists built it deliberately from the classical root to name a systematic class of compounds, which is why it turns up in names like thiophene, a sulfur-containing ring compound.

Synonyms: sulfur-containing, thiol, sulfide, thioether, thiolate

Antonyms: oxo, non-sulfur, oxygen-containing