Translation guide
The English word 'arc' has several distinct meanings: a curved shape, a part of a circle, an electric discharge, and a story or character development. This guide covers the most useful Japanese expressions for each meaning.
Describing something that forms a smooth curve, like a rainbow, a bridge, or a trajectory.
The most direct translation for a geometric or physical arc. Used in mathematics, architecture, and descriptions of shapes.
The rainbow formed a beautiful arc in the sky.
The arc of this bridge is very gentle.
Loanword from English 'arch'. Often used for architectural arches or curved structures, but can also mean 'arc' in some contexts.
Literally 'bow shape'. Refers to something shaped like a bow, an arc. More descriptive and less technical than 弧.
Referring to a segment of a circle's circumference, or a continuous part of a curve.
A luminous discharge of electricity through a gas, like in welding or lightning.
A continuous storyline or the progression of a character over time in a narrative.
Loanword used in media and literature to refer to a story arc. Common in discussions of anime, manga, and games.
The next arc of this anime is very interesting.
Means 'story development' or 'plot progression'. A more native Japanese way to refer to the arc of a story.
Direct loan of 'story arc'. Used in the same way as アーク but more explicit.
This story arc is too long.
弧 (こ) is for physical or geometric arcs. アーク is for electric arcs and story arcs. Using 弧 for a story arc would be unnatural.
The arc of this anime is interesting. (incorrect)
その門は石のアーチでできている。
The gate is made of a stone arch.
月が弓形に見える。
The moon looks like a bow shape.
この曲線は円弧の一部です。
This curve is part of a circular arc.
An electric arc occurred.
His character arc was moving.
The arc of this story was unexpected.