What is the name of a thin French pancake?

A thin French pancake is called a crêpe. It is made from a loose, unleavened batter that spreads into a very thin layer when cooked on a frying pan or griddle.

Crêpes are strongly associated with Brittany in northwestern France, where both sweet crêpes and savoury buckwheat galettes developed. Sweet versions are commonly made with wheat flour and may contain sugar, fruit, chocolate or cream. Savoury galettes traditionally use buckwheat flour and may be filled with ingredients such as cheese, ham and egg.

Unlike American-style pancakes, crêpes usually contain no chemical raising agent, so they remain flat and delicate rather than thick and fluffy. Their batter is liquid enough to spread quickly across the cooking surface, and a crêpe often cooks in only 20–30 seconds per side.

The word comes from the Latin crispus, meaning curled or wrinkled. A famous dessert variation is Crêpes Suzette, in which crêpes are served with a citrus-butter sauce and traditionally flambéed with alcohol.