In calligraphy and typography, two or more letters joined together to create a single character. Among the most common such combinations: ? (a+e) and ? (A+E). Among other letters most commonly combined include oe, fi, ff, and ffl. When cast type was employed (before the digital revolution), a ligature was cast on the same body of type. Kerning, by comparison with ligature, is the technique of adjusting the spacing between two letters to bring them close enough to overlap. Some ligatures, including "?", might be described as made by kerning. The horizontal spaces between lines of type are called leading.(pr. LI-gə-chər)Example ligatures:hand-lettered examples of ligatures formed of the letters F-F, C-T, S-T, F-F-I, F-I, F-L, and T-HAlso see flourish, graphic design, lacuna, leading, letterform, lettering, letter space, placement, space, text, type, and typeface.