To have "The Conn" is to have sole responsibility to control, or direct
by order, the movements of a ship. On a Starfleet vessel, as on it's Terran wet-navy antecedents, this responsibilty resides with the Deck Officer, also known as the Officer of the Day. The conn responsibility must be assigned away temporarily if the assigned officer leaves the bridge, even for such mundane activities as using the head. Even the entrance of the Captain onto the bridge does not automatically assign conn responsibility to him or her, it must be assigned by verbal exchange.
The word "conn" is an ancient one. Original use of this word dates back
to the eleventh century, in England. It comes from the Anglo Saxon word 'conne', which means to know or to be skilful.
The redirect below leads to the Flight Controller page, which
describes the helm and conn functions as being interchangeable. This is not really correct; the helm position can be assigned the Conn, but is not in fact "the Conn".
Most of this information was verified at tolani.edu (a.k.a. the tolani maritime institute) and at navyslang.com.
- REDIRECT flight controller