Meaning and history
Lyndsea is a rare modern spelling variant of Lindsay. Lindsay originated as a Scottish surname derived from the English region of Lindsey in Lincolnshire, whose Old English name referred to the “island” or marshland district of Lincoln. The spelling -sea may encourage a modern association with the ocean, but that is not the historical meaning. Reliable prominent bearers using exactly Lyndsea are scarce, so the established Lindsay surname history provides the most defensible explanation.