According to Dictionary.com the definition of a query as it relates to publishing is:
an inquiry from a writer to an editor of a magazine, newspaper, etc., regarding the acceptability of or interest in an idea for an article, news story, or the like: usually presented in the form of a letter that outlines or describes the projected piece.
So what, I ask you, is a prequery? If a query is “an inquiry regarding the acceptability of or interest in an idea,” then why would you need to prequery, I ask? It amazes me how so many seem to want to waste my time. Maybe that’s the idea: if enough time is spent with one author and queries, prequeries, preprequeries, and simple questions, eventually the agent will just assume they’re working together.
At least once a week I reject a query only to later be berated by the author because in fact it wasn’t a query, but she was just checking to see if it might be something I would be interested in. Or, I actually get queries that state that before querying she just wanted to make sure I’m accepting queries. Huh? And then of course there is the query that’s actually labeled “prequery.”
A query is a query is a query no matter what you want to call it or how you want to spin it. If you don’t feel you’re ready to query then don’t, but don’t waste the agent’s time by tiptoeing around the process. If you are sending any question pertaining to your book you are querying the agent, so make it good.