Erinaceous /ɛ.rɪˈneɪ.ʃəs/ Adj. Hedgehog-like.
Yes, erinaceous is a word that describes something that is similar to a hedgehog. It comes from the Latin word for hedgehog, ērināceus, and I think it is delightful that English has this word. You know, just in case there’s something in our lives which we can only describe as resembling a hedgehog.
Sure, you say, it could just mean spiky, bristly, prickly, or oddly cute. But it doesn’t.
It’s not just the spikiness of a hedgehog that it describes; it’s the entire hedgehogness. So, off the top of my head, this word could apply to; porcupines (“It was erinacious in appearance, but actually of the rodent family“), echidnae (“I thought it was erinaceous until it laid an egg right in front of me!“) and pin-cushions (“Grandma your pin cushion is somewhat erinaceous“). Oh, and hedgehogs, but that’s pretty tautological.
So basically we have an adjective here that has a very limited descriptive range. When using this word, and being pedantic (I can’t imagine a non-pedantic person using this word), you will always have to qualify your statements. You will find somewhat erinaceous, relatively erinaceous and fairly erinaceous but the only truly erinaceous thing in the world is a hedgehog. And there’s no point stating the obvious to the point of redundancy. The only other application is describing erinaceous art, I guess. And who goes around painting pictures of hedgehogs?
This is a word that has one very specific meaning. And that’s a rarity in English. According to the Oxford English Dictionary there are, at the very least, a quarter of a million distinct English words, but if different senses of each word were counted then this number would triple. Meaning that, on average, each word in the English language (and these statistics exclude inflections, technical and regional words) has an average of three meanings or senses.
But not erinaceous, the most specific word in the English language.