noun, noun or participle which takes 'suru', intransitive verb
A light, unintentional sleep, often while sitting or lying down briefly. Can be used as a noun or with する to mean 'doze off'.
ソファでうたた寝してしまった。
I dozed off on the sofa.
うたた寝から目が覚めると
When I woke from my nap, it was dark outside.