noun
full-width space; em space
A space character that occupies the same width as a full-width CJK character, used in Japanese text input and formatting.
日本語入力では、全角スペースと半角スペースを区別する必要がある。
In Japanese input, you need to distinguish between full-width and half-width spaces.
半角スペース is a half-width space, narrower and typically used in ASCII contexts, while 全角スペース is a full-width space matching the width of CJK characters.
Compound of 全角 (full-width) and スペース (space), a straightforward technical term from computing.