Quite simply, a ligature is the combination of two letterforms into
one continuous character. For many people, the most familiar ligature
is the ampersand (&) or and sign. This character is the stylized
abbreviation of "et", the Latin word for "and".
The word "ampersand" is derived from the phrase "and
per se and". Adobe Systems has an overview of this particular
character at its site.
Another common (alleged) ligature is the "at" symbol (@), which has
becomely widely used with the advent of e-mail. Like the ampersand, this character's
origins seem to be derived from Latin, specifically the word "ad",
meaning, logically enough, "at". The Terminal article, Where
it's @ has more information on this character.
Below are some of the ligatures appearing in the standard Western ASCII set.
You may see these used in words such as 'Æsthetic', 'Encyclopædia'
In 1959 Herbert Bayer designed his Fonetik Alfabet as a proposed simplification
of the existing Roman alphabet. This system of writing sought to eliminate the
endless variables found in written language and assign one sound to one letter.
Within this system, double letter and triple letter sounds were also simplified
using ligatures, as illustrated below.
Even ancient Egyptians sought
to simplify common combinations of symbols in Hieroglyphic ligatures.
There are hundreds of examples of this type of pictographic shorthand. Here is
just one example of this type of Picto-ligature.
The crowns of Upper and Lower Egypt each represent their respective kingdoms.
The combined crown represents a united Egypt. The latest (quasi) ligature to
forced onto the world is the Euro, the symbol for the United European currency.