host's entrance to a tea-ceremony room
Specific architectural term in the context of a tea-ceremony room (chashitsu). Refers to the entrance used by the host (teishu) to bring in utensils and serve guests, distinct from the guest entrance (nijiriguchi).
The host brings in the tea bowl through the sadōguchi.
Compound of 茶道 (sadō, 'tea ceremony') and 口 (guchi, 'entrance'). The reading さどう is the standard on'yomi for 茶道 in this context.