A pan sauce is a type of sauce that is often made to accompany sauteed

Sautéing

Sautéing is a method of cooking food, that uses a small amount of fat in a shallow pan over relatively high heat. Ingredients are usually cut into pieces or thinly sliced to facilitate fast cooking. The primary mode of heat transfer during sautéing is conduction between the pan and the food being...

 meats.

Generally speaking, a pan sauce is made by sauteing a meat at high temperature in a skillet, removing the meat, pouring off any excess fat, deglazing

Deglazing (cooking)

Deglazing is a cooking technique for removing and dissolving caramelized bits of food from a pan to make a pan sauce.When a piece of meat is roasted, pan fried or prepared in a pan with another form of dry heat, a deposit of caramelized sugars, carbohydrates, and/or proteins forms on the bottom of...

 the pan with a liquid such as stock or wine, and incorporating the remaining browned material at the bottom of the pan, known as a fond, or more properly sucs, into a basic sauce.

The flavour of the pan sauce is determined chiefly by the meat, the liquid used for deglazing, and any flavouring or finishing ingredients added, such as aromatics, herbs, or butter.