* Sailing: "The sailor adjusted the tack of the sail to catch the wind."
* Horse Riding: "The rider used a tack to secure the saddle to the horse."
* General: "I had to change my tack and try a different approach to solve the problem."
* Metaphor: "He was a master of political tack, always shifting his position to appeal to the largest audience."
* Informal: "I need to get a tack to hang up this picture."
Let me know if you'd like more examples!