köken: Likely a compound of 戸 (to, “door”) + 陰 (kage, “shadow”), possibly from the notion that the lizards live in the shade of doors, or that they live in shadow, especially when indoors, or are thought to be crawling on doors and their dark coloring can be mistaken for their shadow. Alternatively, perhaps from 疾隠 (toku kakure, “quickly hiding”) or 敏駆 (tokake, “nimble runner”). Orthographic borrowing…
köken: rắn (“snake”) + mối (“common house gecko”). See also cá mối (“lizardfish”). The second element is commonly thought be mối (“termite”), which is rationalized as being skinks' preys.