was the ordinary Hebrew
word for "wind
", and thus it was used to mean "breath
", and that vague thing called "spirit
", whatever that's meant to be.
One example is in the opening of Genesis: a great wind moved over the waters, or the spirit of God moved over them (or "on the face of" them). Both these translations are correct, because the expression is ruH 'elohim, where the first word can be wind, breath, or spirit, and the second word is either literally the name of god, or just an intensive word: a great spirit or a spirit of Elohim, or whatever.
The extra A in ruach is an example of so-called pathah furtive, in which the vowel A (indicated by the sign pathah) is put between a long vowel and a final guttural consonant, in this case heth (or cheth). It's written under the guttural, which looks as if it should be pronounced ruHa, but actually it's ruaH. As the extra a wasn't phonemic and might not have been very strong, an equally good transliteration would be ruH.