cover charge

[Matthew Wai]

Whereas if you use the second definition, you do not need an article.

An article is used in the following example, where the second definition is used.
'An appetizer is the first course of a meal.'── quoted from http://www.collinsdictionary.com/di...uild-learners/appetizer?showCookiePolicy=true

How is it different?

The difference is that it is used between dashes and might function as an adjective in your example.