early 15c., "to flood, overflow," from Anglo-French surounder, Middle French soronder "to overflow, abound; surpass, dominate," from Late Latin superundare "overflow," from Latin super "over" (see super-) + undare "to flow in waves," from unda "wave" (from PIE root *wed- (1) "water; wet;" compare abound). Sense of "to shut in on all sides" first recorded 1610s, influenced by figurative meaning in French of "dominate," and by sound association with round, which also influenced the spelling of the English word from 17c. Related: Surrounded; surrounding.
