keyaki, zelkova tree, (kokuji)
欟 is a Japanese-made kanji (kokuji) that refers specifically to the keyaki tree, also known as the Japanese zelkova. Its meaning is narrow and concrete: the tree itself.
欟 is a kokuji created in Japan by combining 木 (tree) with 觀 (view, observe), likely to name the keyaki tree. The exact reasoning behind the choice of 觀 is uncertain.
The left side 木 tells you it's a tree. The right side 觀 suggests looking at or observing—imagine a distinctive tree you'd point out and admire, the keyaki.
For つき, picture the keyaki tree glowing under the moon (月, つき). The moon's light (つき) helps you remember the reading つき.
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