Candidate vs. Lead

These two words have bothered me for quite some time, and for some new sourcers it may be something to learn to differentiate from the beginning. A 'candidate' is not the same as a 'lead', at least not in my book. Why, you may ask? Well, let's start off with their very definitions:

According to Webster's Revised Unabridged Dictionary, a Candidate is:

• One who offers himself, or is put forward by others, as a suitable person or an aspirant or contestant for an office, privilege, or honor; as, a candidate for the office of governor; a candidate for holy orders; a candidate for scholastic honors.

According to WorldNet, a Candidate is:

• Someone who is considered for something

According to WorldNet, a Lead is:

• An indication of potential opportunity

Small, but important differences in my book.

When you give a recruiter a list of names only, those are leads. At this point, they are only potential candidates. The recruiter's responsibility is then to turn them into candidates by qualifying them.
However, if you have found specific information, such as a bio or profile, on these people that would indicate that they have some qualities your recruiter's client has requested, does that make them a candidate? Or are they still considered a lead? I'd like to know the answer to that one.
In the same respect, if you give a resume to a recruiter, is that a candidate or a lead? I would argue candidate because you've probably looked over their qualifications and pre-determined them to be a decent fit for the opportunity based on the specs your recruiter gave you. Some may think differently, however.

I'd be interested in some other thoughts and opinions on this!