This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
椗 combines 木 (tree/wood) with 定, which likely contributes the sound. The exact historical development is uncertain.
The left side is 木 (tree/wood) and the right side is 定 (determine/fix). Picture a wooden stake fixed in the ground, but remember the meaning is uncertain.
For テイ, imagine a wooden table (テーブル, teeburu) fixed in place: the テイ sound is like the start of table, and the wood 木 is part of the kanji.