An autoclave is a technological device used to sterilize medical instruments from microbes and other pathogens. Aboard Federation starships in the 23rd century, this medical device was available for the tools and instruments used by the Starfleet chief medical officer, doctors and nurses.
In the year 2268, James T. Kirk noted Odona examining the autoclave in a facsimile of Doctor McCoy's work area in sickbay aboard a replica of the USS Enterprise. (TOS - Star Trek 6 novelization: The Mark of Gideon)