A chemist would agree with Caroline. Anything that is ionic and soluble, they call "a salt". It's not the name of just one compound to them, it's a class of compounds.
In everyday usage, "salt" used as a proper name means specifically "table salt", i.e. Sodium Chloride. If an omelet recipe calls for salt, they mean food-grade sodium chloride, not magnesium sulfate or ferric hydroxide.
Sometimes in soil science, it seems that when THEY say salt, they mean soluble and ionic, but NOT of value to plants. Thus N, P, K and Sulfate, Ferric and Magnesium ions might not be called "slaty" or 'saliizing since plants will take them up, out of the soil, and utilize them.
But a chemist who is not into soils WOULD call them "salts".
The meaning of word partly depends on who is saying it, or why.
