Definition

Noun: 1. The first feather or down feather of a young bird: The small, soft, fluffy feather that covers the body of a nestling or chick. 2. A down feather that persists in some adult birds: A type of soft, insulating feather found beneath the contour feathers in some mature birds.

Examples

• The newly hatched chick was covered in a soft, gray plumule.
• Ornithologists study the plumule structure to understand avian insulation.
• Unlike the stiff flight feathers, the plumule provides warmth.

Advanced Usage

• In ornithology, the term is used to distinguish the insulating down from other feather types like remiges (flight feathers) or rectrices (tail feathers).
• The presence and density of the plumule are key adaptations for thermoregulation in birds.

Variants and Related Words

• Plumage (n): The entire feather covering of a bird.
• Down (n): A general term for soft, fine feathers, often used synonymously with plumule but can refer to the material from any bird.
• Contour feather (n): The stiffer, outer feathers that give a bird its shape and are used for flight.

Synonyms

• Down feather
• Natal down (specifically for the first feathering of a chick)

Notes on Meaning

The primary and most specific meaning of plumule is a biological term for a type of feather. Its usage is almost exclusively scientific or technical, relating to zoology and ornithology. It is not used in everyday conversation.

Noun

1. down feather of young birds; persists in some adult birds