church

Church comes from Old English ċiriċe, from Proto-West Germanic *kirikā, an early borrowing of Ancient Greek κυριακόν (kuriakón), the neuter form of κυριακός, 'belonging to the lord,' from κύριος, 'ruler, lord.'

Greek speakers began using κυριακόν for Christian houses of worship around 300 CE, though it was less common than ἐκκλησία or βασιλική for that sense. The word passed directly from Greek into Germanic speech, likely through the Goths, and was probably in use among West Germanic peoples even before they became Christian.

It's a doublet of kirk, the Scots word for the same building, and shares its root with German Kirche, Dutch kerk, Danish and Norwegian kirke, and Swedish kyrka — all tracing back to that same Greek 'belonging to the lord.'