Ramekins are small, cylindrical dishes that are used for baking individually-sized dishes. Their size makes them perfect for baking small soufflés, as their straight sides make it easy for an egg white-based soufflé mixture to rise up the sides of the dish and gain height.

They’re perfect for individually portioned soups, desserts, pies, and soufflés; for serving nuts, dips, and small snacks; and even as a stand-in for a mini prep bowl or a salt cellar. Though the straight-sided fluted white dish is still de rigueur, ramekins now come in many different sizes, shapes, and materials.

The term ramekin is derived from the French 'ramequin', a cheese- or meat-based dish baked in a small mold.

More Info: en.wikipedia.org