Proportional space characters: The design of a fount of type in which each characters were assigned a width, known as set, in accordance to its shape. For example, the set for the letter M is three times of the letter I.

• 比例字宽字:一副英文字的设计，各字母宽依照该字的形状，有着不同比例的字宽。例如M字的字宽是I字的三倍等。