What's the difference between martlet and partlet?

Martlet

Definition:

(n.) The European house martin.
(n.) A bird without beak or feet; -- generally assumed to represent a martin. As a mark of cadency it denotes the fourth son.

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Definition:

(n.) A covering for the neck, and sometimes for the shoulders and breast; originally worn by both sexes, but laterby women alone; a ruff.
(n.) A hen; -- so called from the ruffing of her neck feathers.

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