noun

1. a famous strong, swirling tidal current off the W coast of Norway, hazardous to safe navigation
2. any large or violent whirlpool
3. a violently confused or dangerously agitated state of mind, emotion, affairs, etc.

Etymology: 17th-c. Du (now maalstroom) < malen, to grind, whirl round (akin to Ger mahlen: see mill) + stroom, a stream: first applied by 16th-c. Du geographers