Situation: Let's say two neighbors are talking about their neighborhood.
Sentence: ''The houses here has/have many windows''
There is an article, but the noun that it introduces is plural.
Do I use has or have?
Yes, there is a definite article. No, that article does not mark number.
The noun is plural, in both structure and meaning. The verb form that agrees is "have".
The houses here have many windows.
The neighborhood has many windows.
On the other hand, the indefinite article does mark number. We find "a house" to be a perfectly natural and sensible noun phrase, but "a houses" is confusing and (unless "a" represents something other than the indefinite article) just plain wrong.