平 行(へいこう)

へいこう

noun / na-adjective

parallel

See also: 並行(へいこう) (parallel, concurrent)

1. parallel

Lines or surfaces that maintain equal distance and never intersect.

この二(ふた)つの線(せん)は平行(へいこう)だ。

These two lines are parallel.

The railroad tracks run parallel to each other.

Two parallel lines never intersect no matter how far they are extended.

2. simultaneous; concurrent

Doing multiple things at the same time.

To pursue work and studies simultaneously.

We are working on two projects simultaneously.

The discussion remained at a stalemate, and no conclusion was reached.

平行線(へいこうせん) (parallel lines) is used figuratively to mean that two sides cannot reach agreement.

平行(へいこう) has both a geometric meaning (parallel lines) and a figurative meaning (doing things simultaneously).

GEOMETRIC SENSE:

FIGURATIVE SENSE:

平行(へいこう)して進(すす)める: to pursue simultaneously
平行線(へいこうせん)をたどる: to remain at a stalemate (a discussion where two sides never meet, like parallel lines)

RELATED TERMS:

垂直(すいちょく): perpendicular, vertical
並行(へいこう): concurrent, simultaneous (the variant spelling preferred for the "simultaneous" meaning)

NOTE:
平行(へいこう) and 並行(へいこう) are homophones. 平行(へいこう) emphasizes the geometric sense; 並行(へいこう) is preferred for "concurrent" or "alongside."

Related Words

general

Added 2026.1.16 16:37 · Revised 2026.6.7 0:06

05000/05445_heikou