h₃erbʰ-
“to change, to turn over”change allegiance, orphan
Root for changing/being bereft, yielding Greek orphanos, Latin orbus, English orphan.
Discussion
The PIE root *h₃erbʰ- (to change, to pass from one state to another, to turn over) produced vocabulary for transformation and inheritance — including, surprisingly, the word orphan.
Greek orphanós (ὀρφανός, "bereft, deprived, orphaned") descends from this root through the concept of one who has undergone a change of state — specifically, the change from having parents to not having them. The orphan is "the one who has been transformed" by loss. English orphan and the combining form orphano- derive from the Greek.
Latin orbus (bereaved, deprived of parents or children) continues the root in Italic, giving the English word orbit (orbita, a circular path — through a different semantic chain involving orbis "circle," though some scholars connect orbis to this root through the concept of revolution/turning-over).
German Erbe (inheritance, heir) shows a different semantic development: what changes hands at death is the inheritance, and the heir is the one who receives the changed-state property. The connection between orphanhood and inheritance is logical — the orphan inherits because the parent has undergone the ultimate change of state.
The root's semantic core is transformation through loss — a change that leaves someone in a diminished state. The PIE speakers who named this experience generated vocabulary for both the person diminished (orphan) and the property transferred (inheritance).
Notes
Pokorny 781-782. English orphan, robot (Czech robota, from this root via Slavic).