Hystriciasis

(n.) the sensation or condition of hairs standing on end

You might better know it as goosebumps or gooseflesh—or, it you’re a little more classically-influence, as piloerection or horripilation—but there’s also hystriciasis for the feeling of hairs standing on end.

That being said, strictly speaking hystriciasis differs slightly from the other words on offer here in that it was coined as (and, in some contexts at least, remains the name of) a medical condition that causes a permanent hardening or stiffening of body hairs. In both senses, the word is etymologically driven by hystrix, the Greek word for a porcupine.

The word hystriciasis dates back to the early 1800s, when it was first included in a handful of early medical textbooks. It’s been suggested (by the Oxford English Dictionary, among others) that the term was originally coined somewhat in error, as a misunderstanding of another medical condition known as ichthyosis hystrix, or hystricism. Rather than affect the body’s hairs, hystricism is caused by an excess of the hair protein keratin within the skin itself, which causes thickened callus-like growths to appear on the skin’s surface.

Could it really be that, due to its etymological connection to porcupines, these early nineteenth-century medicators misinterpreted the term hystriciasis by presuming that it must refer to the hair, not the skin? It’s certainly possible—and it’s certainly true that it is from there that use of the word has since softened in some contexts, to refer simply to the stiffening or standing on end of any body hair.