noun
church building; cathedral; chapel
Refers specifically to the physical building used for Christian worship, not the congregation or institution.
この町には古い教会堂がいくつか残っている。
Several old church buildings remain in this town.
教会 is the general word for 'church' (both building and congregation), while 教会堂 emphasizes the physical structure.
Compound of 教会 (church) + 堂 (hall, building). A straightforward Sino-Japanese construction.