Distance between printed text characters. This spacing is adjustable to increase or decrease the average distance between letters. Can be applied to a block of text or paragraph. ‘Proportional letter spacing,’ adjusts the horizontal space between two characters based on the contours of their shape. A ‘monotype letter spacing’ has fixed horizontal spacing between printed characters, regardless of their shape or contours. As an example, the letter ‘i’ normally takes less space than the letter ‘m’ in the word ‘main.’ Also known as tracking.