also: ほうどう
noun
lecture hall (Buddhist temple, esp. Zen)
A hall within a Buddhist temple where the abbot or senior monk delivers sermons; especially associated with Zen temples.
禅寺の法堂で老師の説法を聞いた。
I listened to the master's sermon in the lecture hall of the Zen temple.
本堂 is the main hall housing the principal image, while 法堂 is specifically for lectures and sermons.
From Middle Chinese 法堂 (pjuwop dang), literally 'dharma hall'. The reading はっとう reflects a regular sound change from ほうどう.