The connecting link between two letters that are joined together. Also, two or more characters that are combined into one Glyph, generally comprising such characters as ﬁ, ﬂ, ﬀ, ﬃ, ﬄ etc.
When type was made of metal, ligatures were a physical necessity to stop one piece of metal clashing with another: it was physically impossible for strokes to overlap. Not so with digital strokes: so nowadays, ligatures have primarily aesthetic benefits. Some ligatures, such as the common ﬁ may merely prevent the collision of two glyphs, but others such as the OO ligature provide a decorative, ornamental quality.
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