The mark for a paragraph. A fragment as it appears in this library, not an English word.
Greek παράγραφος (paragraphos, a mark written beside the text), from para- (beside) + graphein (to write); the letter here is a fragment standing for the word it abbreviates, not a word on its own.
The mark for a paragraph, kept here as the fragment it actually is in this library rather than dressed up as an English word.