early 15c., "to put in possession of a person," from Old French vestir "to clothe; get dressed," from Medieval Latin vestire "to put into possession, to invest," from Latin vestire "to clothe, dress, adorn," related to vestis "garment, clothing," from PIE *wes-ti-, suffixed form of *wes- (2) "to clothe," extended form of root *eu- "to dress." Related: Vested; vesting.
<a href="https://www.etymonline.com/word/Vested">Etymology of Vested by etymonline</a>
Harper, D. (n.d.). Etymology of Vested. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/Vested