Pearl Harbor

WordReference Random House Unabridged Dictionary of American English © 2025

Pearl′ Har′bor, 

1. Place Names a harbor near Honolulu, on S Oahu, in Hawaii: surprise attack by Japan on the U.S. naval base and other military installations December 7, 1941.
2. any significant or crippling defeat, betrayal, loss, etc., that comes unexpectedly.

Collins Concise English Dictionary © HarperCollins Publishers::

Pearl Harbor noun

1. an almost landlocked inlet of the Pacific on the S coast of the island of Oahu, Hawaii: site of a US naval base attacked by the Japanese in 1941, resulting in the US entry into World War II