I learned that 마디 could be used as a countword for words. Indeed, the dictionary has examples like "한 마디도 안 했다" - I didn't say a word.
However, I'm reading an article (here, unfortunately behind a paywall) about word frequencies, and some data given includes a corpus (collection of texts; 말뭉치 in Korean) with a 마디수 of 2,881,175 and 어절의 수 of 529,758. I know 어절 is used to denote a string of text delimited by spaces (so the word + all the endings is 1 어절), but then what is 마디수? Is it morphemes, or syllables, or something else?
If it's each morpheme (base word and all endings counted separtely), then the ratio isn't high enough (there should be about 1.8 morphemes per 어절 in Korean, from my experience).
마디is a syntactic word, the one separated by spaces.
한마디here is a single compound word, meaning “a short comment.” It should not have a space in it.