A screw was a small metal object used to join different parts of a structure together. Screwdrivers were used to enable the tightening and loosening of screws. (PRO: "Time Amok")
Sometime before 2152, a young Trip Tucker removed the screws from his family's dining room table on Thanksgiving. (ENT: "Observer Effect")
In 2366, Paul Stubbs dismissed concerns about the sentience of the nanites, calling them "machines with a screw loose", a fact which Data disputed, giving their intelligent actions as evidence. (TNG: "Evolution")
In 2375, Tom Paris cautioned Chakotay about a sentient missile's internal sensor array, warning that if they tried to even loosen a screw, it would explode. (VOY: "Warhead")
By 2383, screws with Starfleet deltas were available to use, along with screwdrivers with corresponding heads. (PRO: "Time Amok")