In typography, we speak of readability when we discuss how easily a text is read. The readability of a text is influenced by many aspects (listed in the quote below) other than the text itself. Readability is a concept often mixed up with legibility.

QUOTE

“The readability of a text is influenced not only by the choice of typeface, type size, correct or incorrect letter and wordspacing, and the length of line, but also by the linespacing or interlinear space, often termed ‘leading’.”

Jost Hochuli (translated by Charles Whitehouse) in Detail in typography.