Well, FWIW I think the chess definition of strategy and tactics differs from what some of the other posters are talking about in a non-chess setting.
That is, I don’t think that most chess players would say that tactics are the individual moves that are part of an overall strategy. This definition kind of renders “tactics” meaningless because as long as you have an overall strategy then whatever you are doing to achieve it is tactical. Rather, to me any given move has a certain degree of tactical or strategic significance; and if one move has both, the more the better. So, “tactics” doesn’t necessarily mean the individual moves that make up a strategy; one could implement a strategy without using any tactics at all.
I don’t think I’m really explaining this very well at all. Let’s say white does a neat little knight fork that enables him to win the exchange. Well, that was neat bit of tactics that may help him down the road because of the material advantage, but it could be the case that the knight move wasn’t really party of the overall strategy (of queendside expansion, control of the center, etc.).
Therefore, I see a tactical move as being a slight diversion from the main strategy that garners other advantages (e.g., material, initiative) of a more immediate nature than does strategy. The strategy is necessary, however, to make the more immediate benefit of a bit of tactics pay off.