A field docent was a Trill representative of the Trill Symbiosis Commission who evaluated prospective hosts of Trill symbionts.
In 2370, Jadzia Dax was assigned as Arjin's field docent. Jadzia mentioned to Arjin that her field docent had been Curzon Dax. (DS9 episode: "Playing God")
Enrak Grof's field docent recommended that Grof not be joined with a symbiont. The docent had seventeen other Trill to choose from at the time. (TNG - The Dominion War novel: Behind Enemy Lines)