I have no idea what that term means. What was the context?

Salts are any soluble minerals in the soil. This includes sodium, potassium, calcium, magnesium, and others. Some are essential nutrients and others are not. All soils contain some amount of salts. Additional salts are added with irrigation water and fertilizers.When the total amount of salts gets too high, it interferes with water and nutrient uptake, and cellular function. Plants are not "allergic" to salts since they have no immune system. Some plants are more tolerant of higher salt soils than others. Hope this helps.

Way to go botanybob!!! Great answer.