noun
second wave
Used for a second surge or phase, especially in contexts like epidemics, trends, or social movements.
専門家は第二波の到来を警告した。
Experts warned of the arrival of a second wave.
感染の第二波に備えて医療体制を強化する。
Strengthen the medical system in preparation for a second wave of infections.
Compound of 第 (ordinal prefix) + 二 (two) + 波 (wave). A straightforward Sino-Japanese formation.