For the similarly named equestrian gear, please see tack.
Tacking was the act of changing course by turning into one's source of propulsion.
For most of the trip on Sisko's lightship, Benjamin Sisko told Jake Sisko they'd be tacking into the light. Later, due to the spill off the sails, Benjamin didn't think they would be able to make much headway with each tack. (DS9: "Explorers")
The Star Trek: Deep Space Nine episode "Tacking Into the Wind" is a reference to this term.