Origin: 1400–50; late Middle English surounden to inundate, submerge < Anglo-French surounder,Middle French s(o)ronder < Late Latin superundāre to overflow, equivalent to Latin super-super- + undāre to flood, derivative of unda wave (see undulate); current spelling by analysis as sur-1 + round1 (v.)
1423, "to flood, overflow," from M.Fr. soronder "to overflow, abound, surpass, dominate," from L.L. superundare "overflow," from L. super "over" (see super-) + undare "to flow in waves," from unda "wave" (see water; and cf.
abound). Sense of "to shut in on all sides" first recorded 1616, influenced by figurative meaning in Fr. of "dominate," and by sound association with round. First record of surroundings in sense of "environment" is from 1861.