subdial1
/ˈsʌbˌdʌɪəl/noun
A subsidiary (and usually smaller) dial, especially one set within a clock face or display panel which shows additional information.
Origin
Late 19th century; earliest use found in The Manufacturer and Builder. From sub- + dial.
subdial2
/ˌsʌbˈdiːəl/rare
adjective
= sub dio.
Origin
Mid 17th century; earliest use found in Nathaniel Bacon (bap. 1593, d. 1660), politician and author. From classical Latin subdīālis exposed to the open air from sub diū in the open air (from sub + diū, inflected form (perhaps locative) of diūs day, old nominative form subsequently replaced by diēs: see diurnal) + -ālis.