I play Scrabble. I'm learning words with the letter 'q'. What is the usage of the word 'qua'?
It's from Latin, meaning "what" or "as." The entry at Dictionary.com gives this example:
"The work of art qua art can be judged by aesthetic criteria only."
The point (aside from sounding a little pretentious) would be to contrast "art qua art" with, say, "art as a commercial enterprise" - where the criteria would be whether a particular piece is salable.
It's also used as part of the phrase (also from Latin) "sine qua non," meaning something essential to something else ("money is sine qua non for an American political campaign").
Qua can usually be read as the word "as".
It is an occasionally useful (and rarely used) link-word in English. I was just reading about qua in Fowler's (incl. the 3rd ed by Burchfield) a couple of days ago. Says Fowler: "The real occasion for the use of qua occurs when a person or thing spoken of can be regarded from more than one point of view or as the holder of various coexistent functions, and a statement about him (or it) is to be limited to him in one of these aspects":
Here, "the lover aspect is distinguished from another aspect in which he may be regarded. The two nouns (or pronouns) must be present, one denoting the person or thing in all aspects (he), and the other singling out one of his or its aspects (lover, or citizen)."
This was the only way in which Fowler preferred the word be used, but in fact (notes Burchfield), it's often used in other ways:
But the word can seem pretentious, so you may want to avoid it — it usually adds nothing over "as", anyway.
(Burchfield ends with: "And as to usage, as is often the better choice of word, qua word.")