In Greek, the adjective kyriak-ós/-ē/-ón (κυριακόν) means "belonging, or pertaining, to a Kyrios" ("Lord"), and the usage was adopted by early Christians of the Eastern Mediterranean with regard to anything pertaining to the Lord Jesus Christ: hence "Kyriakós oíkos" (Kυριακός οίκος) ("house of the Lord", church), "Kyriakē" (Κυριακή) ("[the day] of the Lord", i.e. Sunday), or "Kyriakē proseukhē" (Greek: Κυριακή προσευχή) (the "Lord's Prayer").
is an Old English word for churches and church property
In standard Greek usage, the older word "ecclesia" (Greek: ἐκκλησία, ekklesía, literally "assembly", "congregation", or the place where such a gathering occurs) was retained to signify both a specific edifice of Christian worship (a "church"), and the overall community of the faithful (the "Church"). This usage was also retained in Latin and the languages derived from Latin (e.g. French église, Italian chiesa, Spanish iglesia, Portuguese igreja, etc.), as well as in the Celtic languages (Welsh eglwys, Irish eaglais, Breton iliz, etc.) and in Turkish (kilise).
In the Germanic and some Slavic languages, the word kyriak-ós/-ē/-ón was adopted instead and derivatives formed thereof. In Old English the sequence of derivation started as "cirice", then Middle English "churche", and eventually "church" in its current pronunciation. German Kirche, Scots kirk, Russian церковь (tserkov), etc., are all similarly derived.