This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 兏 is uncertain. It visually contains the enclosure 厂, but the origin and original component relationships are unclear.
The outer shape 厂 looks like a cliff or shelter, and the inner strokes suggest something long or extended underneath. Picture a long object stored under a cliff overhang, but remember the meaning is uncertain.
For チョウ, imagine a long (ながい) object under the cliff that belongs to a chief named Chou: Chou -> チョウ, and the long object is his.