A tombolo is a coastal landform where an island is connected to the mainland or another island by a narrow strip of sand or gravel, formed by the deposition of sediments in the wave shadow of the island. Tombolos are significant in coastal geomorphology for understanding sediment transport, wave dynamics, and the formation of coastal features.
Source Masselink, G., & Hughes, M. G. (2003). “Introduction to Coastal Processes and Geomorphology.” Hodder Arnold.