the.com/rockpool

means A small pool of seawater left behind in rocks along the shore when the tide goes out, often holding tiny trapped crabs, anemones, and fish until the sea returns.

from A plain, transparent compound — 'rock' plus 'pool' — stitched together in English as people simply named what they saw at the shoreline. No hidden roots or borrowed myths here; it's a descriptive word of the kind that forms naturally whenever a landscape feature needs a name badly enough that nobody bothers inventing something fancier.