The act of bowing
Bowing was the act of lowering oneself in order to show respect or worship.
In 2259 of the alternate reality, James T. Kirk stole a scroll written in the Nibiran language as a distraction so that the Nibirans wouldn't notice his crew's attempts to intervene in the impending volcanic eruption. When Leonard McCoy asked him what he'd taken from them, Kirk replied, "I've no idea, but they were bowing to it." (Star Trek Into Darkness)
In 2267, James T. Kirk assured Apollo that "we don't bow to every creature who happens to have a bag of tricks." He later attempted to defy Apollo, saying if the god wanted Kirk and his crew to bow, he'd have to do something first, but was interrupted by being choked by the god. (TOS: "Who Mourns for Adonais?")
In 2369, a Bajoran captain bowed out of respect towards Kai Opaka as she prepared for her trip through the Bajoran wormhole. (DS9: "Battle Lines")