Purchasing
If you are a stickler you can purchase some Novelty Measuring Spoons that include a spoon for “Pinch.”
Culinary Uses
When used in cooking a "Pinch" is not a precise measurement but its roughest equivalent is 1/2 teaspoon.
Sticklers can measure a “Pinch” but it usually just means a generic small amount, to taste secured between the thumb and index finger.
To learn how to properly fill and measure a “Pinch” of dry ingredients join Smart Kitchen.