A large, often decorated initial letter used to mark the beginning of a verse, chapter, or section in a manuscript or printed book.
Definition
A versal is a large initial capital letter, often ornamental, used to mark the beginning of a verse, chapter, paragraph, or other textual division. The term derives from the Latin versus ("verse") and has its roots in the manuscript tradition, where scribes and illuminators would draw elaborate initials in contrasting colors or with gilded decoration. In printed typography, versals survive as drop caps, raised caps, and decorative initials. They serve both a functional purpose — signaling a new section to the reader — and an aesthetic one, adding visual richness to the page.
Source
No access — Robert Bringhurst — p. 346:
A large initial letter, often decorated.