Your best to confirm with the particular person as there isn't full standardization.

From the submissions guidelines of a publisher http://www.edgewebsite.com/authors.html. They consider it separate.

What to Submit

Required Extras (see below)
Query/Cover Letter (see below)
Synopsis (see below)
Title Page (see below)
Prologue (optional) (see below)
Chapters One, Two, Three (do not send more chapters) (see below)

Your best to confirm with the particular person as there isn't full standardization.

From the submissions guidelines of the publisher Edge Science Fiction and Fantasy, they consider it separate.

What to Submit

1. Required Extras (see below)
2. Query/Cover Letter (see below)
3. Synopsis (see below)
4. Title Page (see below)
5. Prologue (optional) (see below)
6. Chapters One, Two, Three (do not send more chapters) (see below)