Alkyl

Part of speech: noun

Pronunciation: /ˈælkaɪl/

Definitions

1. A substituent group in organic chemistry, formed by the removal of one hydrogen atom from an alkane, that can affect the structure and reactivity of compounds
2. A carbon-based chain created by alkane dehydrogenation, used to denote molecular structures in organic chemistry and impact reaction pathways
3. A hydrocarbon moiety derived from an alkane by eliminating a hydrogen atom, which can alter molecular interactions and character in various compounds

Etymology: The "-yl" ending is the element that matters here. It was added to form names for hydrocarbon groups, the part of a molecule left after a hydrogen is removed from an alkane, which is how "alkyl" came to name the groups attached to the alcohol family. The first half, "alc", comes from "alcohol", which passed into English from medieval Latin "alcohol", a borrowing of Arabic "kuḥl", a fine powder used as eye cosmetic. The Arabic word traces back through Aramaic and Akkadian, and it originally described a powder of antimony, not a drinkable spirit. Its sense only broadened in the early modern period, which is why the chemical family named from it sounds so far from makeup.