What is the definition of a sentence, paragraph and section in Vim?

A sentence is defined as ending at a ‘.’, ‘!’ or ‘?’ followed by either the end of a line, or by a space (or two) or tab. Which characters and the number of spaces needed to constitute a sentence ending is determined by the ‘joinspaces’ and ‘cpoptions’ options. A paragraph begins after each empty line, and also at each of a set of paragraph macros, specified by the pairs of characters in the ‘paragraphs’ option. A section begins after a form-feed (<C-L>) in the first column and at each of a set of section macros, specified by the pairs of characters in the ‘sections’ option.