first wave
Used for the initial wave of a phenomenon, such as an epidemic, attack, or trend. Often appears in news and analytical contexts.
The first wave of the novel coronavirus arrived in spring 2020.
We somehow repelled the enemy's first wave of attacks.
Standard kanji spelling.
Variant using Arabic numeral 1; common in news headlines and technical writing.
Compound of 第一 (first) and 波 (wave). The reading だいいっぱ follows regular rendaku voicing of は to ぱ after ん.