corpus

Corpus, corporis is third declension NEUTER: nominative and accusative corpus, plural corpora, and the genitive gives you the stem corpor-.

That shift from s to r in the middle is rhotacism, a sound change that ran through early Latin and turned an s between two vowels into an r. It is why this noun looks irregular and is not, and once you have seen it you will spot the same pattern in opus and operis, tempus and temporis, genus and generis, and in the verb sum, where es-se gave er-am and er-o.

Of the living it is the body, and set against animus it is the standard half of the Roman mind-and-body pair. Of the dead it is the corpse, and Latin does not need a separate word. Scholarly and legal Latin extends it to any organised whole, which is where the Corpus Iuris Civilis gets its name, and where the linguists' corpus, the body of texts a word count like this one is drawn from, gets its own.

English took corporal, corporate, corporation, corpse, corpuscle, corset and, through French, corps.