前線

• Reading: ぜんせん
• Romaji: zensen
• Kanji breakdown: 前 (zen) — front, before; 線 (sen) — line, boundary
• Pronunciation: /zeɴ.seɴ/

Meaning

Front (weather). A boundary between two air masses of different temperature or humidity.

A noun with two primary meanings: a weather front (meteorological) and a battle front (military). In weather contexts, it refers to the boundary where warm and cold air masses meet, causing rain or storms. Common compounds include 梅雨前線 (tsuyu zensen, the seasonal rain front) and 寒冷前線 (kanrei zensen, cold front). The meteorological usage is very common in daily weather reports.

Examples

1. 前線の影響で今週は雨が続くでしょう。 Rain will continue throughout the week due to the influence of a front.
2. 梅雨前線が本州付近に停滞している。 The seasonal rain front is stalling near Honshu.
3. 前線が通過したあと、気温が急に下がった。 After the front passed, the temperature dropped sharply.

Usage Guide

Context: weather forecasts, meteorology, news

Tone: neutral

Origin & History

From Sino-Japanese: 前 (zen, front/before) + 線 (sen, line). Originally a military term meaning 'front line,' later adopted by meteorology to describe the boundary line between air masses.

Cultural Context

Era: Modern

Generation: All ages

Social background: Universal