wall around market place
闤 centers on a wall that encloses a market area, forming a boundary around the marketplace.
闤 combines 門 (gate) with 睘, which likely contributes the sound and relates to encircling or surrounding, together suggesting a walled market enclosure.
The gate 門 surrounds the inner part 睘, like a protective wall encircling a busy marketplace.
For カン, imagine a can of goods being sold inside the walled market: can -> カン, and the wall keeps the market contained.