This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
庢 combines 广 (building) with 至 (arrive), but the exact historical development and original meaning are uncertain.
The building 广 contains 至 (arrive), but the overall meaning is unclear. Picture someone arriving at a building only to be stopped or blocked.
For チツ, imagine a person arriving at a building and being stopped by a gate that makes a sharp 'chitsu' sound as it closes: chitsu -> チツ.