sebaceous

Before it became a clinical word, Latin sēbum meant something wonderfully unglamorous: tallow, suet, or grease. Physicians borrowed it into English in 1728 for the oily material produced by skin glands, and sebaceus—literally “of tallow”—gave us sebaceous. The proposed prehistoric connection to Proto-Indo-European *seyb-, “to pour out,” may also link this family to soap through Germanic, although the etymology is disputed: de Vaan, for example, is skeptical that Latin sebum and soap are relatives. Either way, the image is memorable—a tiny gland pouring out a waxy coating, rather like a microscopic candle maker working beneath the skin. So when you see sebaceous, picture “tallow-related,” not merely “badly oily”: your face is carrying a pocket-sized Latin word for grease.