Before measuring cups were used for precision measuring, cooks used certain terms to describe measurements. Terms such as "pinch" and "dash" were used to describe small amounts of a seasoning, such as salt or pepper, that would be added to recipes.
Sometimes a recipe calls for a pinch of something. Recipe Hut describes a pinch as a measurement in which you use your thumb, index finger and middle finger to grab the spice. A small pinch, then, is using just your index finger and thumb. Some websites, such as Ochef and Accuracy Project, state that a pinch equates to 1/16 teaspoon.
A dash of something measures out to be slightly more than a pinch. According to Recipe Hut and Ochef, a dash is at least 1/16 teaspoon but less than 1/8 teaspoon. However, Accuracy Project states that a dash measures exactly 1/8 teaspoon.
In addition to pinch and dash, other cooking terms were used to describe small amounts of an ingredient. For example, "smidgen" is used to describe a measurement of 1/32 teaspoon, and "tad" can be used to describe a measurement of 1/8 teaspoon.