A handle was part of a tool that could be grasped by hand.
In 2022, when an alternate future version of James T. Kirk was driving a stolen Dodge Challenger Hellcat and La'An Noonien-Singh was riding shotgun; when he sped up in order to keep up with the van he was pursuing, he told her to "hold on." She then immediately grasps the grab handle in the car. (SNW: "Tomorrow and Tomorrow and Tomorrow")
The Hill People of the Argus River region on Rigel IV used murinite to make the handles of a type of knives which they produced; one such weapon was involved in a series of murders on Argelius II in 2267. (TOS: "Wolf in the Fold")
Aboard Constitution-class starships, it was necessary to turn a handle aboard a turbolift before giving a voice command indicating the destination. This confused both Julian Bashir and Miles O'Brien when they found themselves transported back in time and needing to infiltrate the USS Enterprise. Confused as to why their voice commands were not working, they attempted to remove a wall panel before one of the vessel's crew entered and used the handle. (DS9: "Trials and Tribble-ations")
The Runaway, an ground vehicle on the USS Protostar, was equipped with what Hologram Janeway called "hold-on-to-your-butts grab handles." (PRO: "Dream Catcher")