桜さくら前ぜん線せん

さ

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ぜ

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せ

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Meanings

1

noun

cherry blossom front

A meteorological term for the line connecting points where cherry blossoms are expected to open on the same date, used in spring forecasts.

cherry

前in front, before

線line, track

桜さくら
桜 is the cherry tree or its blossoms, while 桜前線 specifically refers to the forecast line of blooming dates.
前ぜん線せん
前線 means 'front' in meteorology (e.g., 寒冷前線 cold front); 桜前線 applies this concept to cherry blossom blooming.

Compound of 桜 (sakura, 'cherry blossom') and 前線 (zensen, 'front line'), coined as a meteorological analogy.