Definition from Wiktionary, the free dictionary
See also: full-width
fullwidth (not comparable)
- (computing, typography) Of a text character, occupying the space of two alphanumeric characters in a monospace font, or two "normal" text columns.
- Chiefly relevant to CJK monospace fonts, where alphanumeric characters are normally halfwidth and Asian characters (Chinese characters, kana, etc.) are normally fullwidth. However, there are designated halfwidth kana and fullwidth alphanumeric characters that may appear in any CJK font, monospace or proportional, and Chinese characters are almost always "fullwidth".
occupying two columns on a traditional text display
Letters in fullwidth form