並行

• Reading: へいこう
• Romaji: heikō
• Kanji breakdown: 並 (hei/nami) — side by side, line up; 行 (ko/iku) — go, proceed
• Pronunciation: /he.i.ko.ː/

Meaning

Parallel; simultaneous; concurrent. Describes two or more things advancing side by side without converging.

As a verbal noun, 並行する means 'to run in parallel.' Used in both physical and abstract contexts — parallel lines, simultaneous negotiations, or concurrent tasks. The adverbial form 並行して (in parallel with) is extremely common. Contrasts with 直列 (in series). 並行輸入 (parallel import) is a well-known compound.

Examples

1. 二つのプロジェクトを並行して進めることで、納期を短縮できた。 By advancing two projects in parallel, we were able to shorten the delivery deadline.
2. 外交交渉と経済制裁が並行して実施された。 Diplomatic negotiations and economic sanctions were implemented simultaneously.
3. 並行輸入品は正規品より安いが、保証が受けられない場合がある。 Parallel imports are cheaper than official products, but may not be covered by warranty.

Usage Guide

Context: business, diplomacy, technical, daily life

Tone: neutral

Origin & History

Compound of 並 (hei/nami, side by side, row) and 行 (ko, go, proceed). Together they describe the state of moving forward side by side without meeting — a geometric metaphor extended broadly to concurrent processes.

Cultural Context

Era: Modern

Generation: Adults

Social background: Educated