English

subdial

From sub- + dial.

Formed from sub- + dial

Proto-Indo-European *upó ‘up; from below’

Proto-Italic *supo ‘under’

Latin sub ‘under, beneath, below’

English sub-

Proto-Indo-European *dyew- ‘sky, heaven’

…

Latin diēs ‘day’

Latin diālis ‘daily, concerning the day’

Middle French dyal

Middle English diall ‘a pointer on a dial’

English dial

Today it means

noun A secondary dial set into the face of a dial.

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