English

hypnospectrogram

From hypno- + spectrogram.

Proto-Indo-European *supnós ‘sleep’

Proto-Hellenic *húpnos

Ancient Greek ὕπνος ‘sleep’

Today it means

noun A graphical representation of a person's pattern of sleep, obtained via EEG

Language periods are conventional ranges, not dates for this word.

Etymograph / hypnospectrogram