Keyword(s):

The word (or words) a searcher enters into a search engine’s search box.  Also the term that the marketer hopes users will search on to find a particular page.

I think keywords are pretty self explanatory and don’t need my take on it :).
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Glossary Definition From ABC’s of Online Marketing by Alexandra Wharton, Issue 22, Revenue [...]

Keyword Popularity:

A measure of the most frequent words and phrases used in web searches.  Marketers can use KP to determine which keywords bring large numbers of potential customers to a website.  Keywords are stored in the meta tags or text of a web page.

The first step to successful SEO is to identify the KP of [...]

Keyword Domain Name:

The use of keywords as part of the URL to a website.  Positioning is improved on some search engines when keywords are reinforced in the URL.

Many people take advantage of this in buying their domains, not just because of the improved results with the search engines, but to keep the URL as relevant [...]

Quality Score:

Reflects an ad’s historical CTR, keyword relevance, landing page relevance, and other factors proprietary to Google.  Yahoo refers to it as a Quality Index.

Of course getting the most links to your website isn’t always the name of the game; it’s getting high quality links.  This is why spammers who link to your content aren’t [...]

Query:

The word (or words) a searcher enters into a search engine’s search box.

Also referred to as keywords or key phrases, it’s the results of that search that PPC marketers are bidding on and what SEO teams are improving their websites to get into.
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Glossary Definition From ABC’s of Online Marketing by Alexandra Wharton, Issue 22, Revenue [...]