swallow
鷾 refers specifically to the swallow, a type of bird.
鷾 combines 意 (thought, mind) with 鳥 (bird). The exact historical reason for this combination is uncertain; it may be a phono-semantic compound where 意 contributes the sound イ and 鳥 indicates a bird.
The left side 意 suggests an idea or thought, and the right side 鳥 is a bird. Imagine a thoughtful bird that carefully chooses where to nest—a swallow.
For イ, picture an eagle (イーグル) that looks like a swallow but is actually a different bird: eagle -> イ, and the swallow is the thoughtful bird on the right.
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