A down pillow is a type of pillow filled with the soft, fluffy undercoating of ducks or geese, known as down. This natural material provides excellent insulation and comfort, making down pillows popular for their luxurious feel. They are lightweight and moldable, allowing users to adjust the pillow's shape for optimal support during sleep. Down pillows come in various firmness levels, catering to different sleep preferences. They are often covered with cotton or other breathable fabrics to enhance comfort. However, it's important to note that some people may have allergies to down or prefer synthetic alternatives for ethical reasons.