Tsp is the abbreviation for teaspoon, a unit of measurement used in cooking and baking. When a recipe calls for 1 tsp of vanilla extract or 2 tsp of cinnamon, it means you should measure that amount using a standard teaspoon measure.

A teaspoon equals about one-third of a tablespoon, or roughly 5 milliliters if you're using the metric system. Measuring spoons usually come in sets with different sizes: a tablespoon (Tbsp), a teaspoon (tsp), and smaller fractions like a half-teaspoon or a quarter-teaspoon.

When you're following a recipe, using the right amount matters: too much baking soda (measured in teaspoons) can make cookies taste bitter, while too little salt might leave food bland. Professional bakers and cooks take measurements seriously because precision often makes the difference between success and disappointment.

You might also see “t” as an abbreviation for teaspoon in older cookbooks, though “tsp” is more common today.