a small wave or series of small waves on the surface of water or another liquid.

水面などの小さな波・さざ波

a small, spreading effect or reaction (often used figuratively, e.g., a ripple of laughter or concern).

（比喩的に）広がる小さな影響や反応（例：笑いの波紋）

to form small waves on the surface (of water or another liquid).

（水面などが）小さな波を立てる

to spread gradually outward or cause something to spread in small effects or reactions.

徐々に広がる・（影響などを）徐々に広げる