What is the abbreviation for teaspoonful?

The abbreviation for teaspoonful is "tsp." This is a widely accepted and recognized shorthand used in cooking and medication dosages to denote a teaspoon. It helps to simplify recipes and instructions, ensuring clarity in communication regarding the volume of ingredients or medications.

The other options, while similar, are not the standard abbreviation for a teaspoon. "tbsp," for instance, is the abbreviation for tablespoon, which is a different measurement. "tspn" and "tspful" are lesser-known variations and not commonly used in practice. Therefore, "tsp" is the correct and most universally understood abbreviation for teaspoonful.