Dockmaster was the title given to a person who managed drydock or spacedock facilities. The dockmaster's office managed flight traffic in and around these facilities, authorizing arrivals and departures.
In 2269, Hikaru Sulu cleared the Enterprise for departure with Starbase 16's dockmaster and proceeded to the starting line for The Great Starship Race. Shortly afterward, Commander Spock asked that the dockmaster moor the Romulan Stormbird-class Red Talon while Captain James T. Kirk contacted the starbase's magistrate with a coded signal. (TOS novel: The Great Starship Race)
Early in the 2270s, Indalo Station's dockmaster accepted payment for docking rights from Kirk, who traveled clandestinely with Leonard McCoy in an Andorian merchant ship formerly belonging to George Samuel Kirk, Jr.. (TOS - Mere Anarchy novella: Shadows of the Indignant)
The dockmaster of the Hus-24 drydock personally greeted Kirk and Spock when the Enterprise docked for biannual maintenance duty in February 2274. After their account was settled, however, he stunned them both with a phaser. (TOS comic: "Husian Gambit")