字送り

字 (“character”) +‎ 送り (“sending; feed”)

字(じ)送(おく)り • (jiokuri) 

1. a carriage return (The action on a typewriter or printer that returns it to the beginning of the line)

   Coordinate term: 行送り (gyōokuri)

2. (typography) the distance between the two center points of the advance widths of two successive monospace CJK characters, sometimes mistranslated as "tracking" by Western software localizers

   Coordinate terms: 行送り (gyōokuri), 字間 (jikan)

• 字送り (jiokuri) is a unique concept to East Asian typography, with no Western equivalent. This is due to how CJK characters are mostly monospace, meaning that this measurement is uniform; meanwhile in Western typography, characters have proportional width, which would render an equivalent measurement useless. Some software localizers use this term as a translation of tracking, while others keep them separate and use the transcription トラッキング (torakkingu) instead. Tracking corresponds better to 字間 (jikan). Mathematically speaking, 字送り (jiokuri) = 字間 (jikan) + font size. 字送り (jiokuri) can be measured in points or 歯 (ha).