imbricate

the entry in merriam webster's entry says it is related to greek ombros or rain. baffling. googled more and found this here

Etymology [of imbricate]: The ancient Romans knew how to keep the interior of their villas dry when it rained. They covered their roofs with overlapping curved tiles so the "imber" (Latin for "pelting rain" or "rain shower") couldn't seep in. The tiles were, in effect, "rain tiles," so the Romans called them "imbrices" (singular "imbrex"). The verb for installing the tiles was "imbricare," and English speakers used its past participle -- "imbricatus" -- to create "imbricate," which was first used as adjective meaning "overlapping (like roof tiles)" and later became a verb meaning "to overlap." .

intricate. tessellate is also a form of tiling but involves no overlap. tessellate traces back to tessera(e) which are square tablets used in mosaics and ultimately going back to tetra(gk four).