Literally "under Jove", from sub (“under”) + ablative of Iovis (“Jupiter, god of the sky”).
sub Iove (not comparable)
- (figuratively) under the Jovian sky, under the open sky, in the open air, outside.
8 CE,
Ovid,
Fasti 2.299–300:
- sub Iove dūrābant et corpora nūda gerēbant
docta gravēs imbrēs et tolerāre Notōs.- [Living] under the open sky they were toughened up, and displayed their bodies naked,
trained to endure heavy rains and southern winds.