Keeill (also keill, keeil; plural kialteenyn) is a Manx Gaelic word for a chapel.
The word is a Gaelic loanword from Latin cella, which originally meant a storeroom, or a small room. In both English, and the Goidelic languages, the word was borrowed in the sense of a monastic cell. In English, the word "cell" has also taken on the additional meaning of a room in a prison.
The word, in its various forms, can be found in Irish and Scottish Gaelic too. It is often anglicised in Scotland and Ireland as "Kil-" e.g. Kilmarnock, Kildare etc.
Columba is known as "Columb Killey", where killey is the genitive of keeill in Manx. Calum Cille etc. in the other Goidelic languages.
Archaeologically, it is used for a specific type of small simple chapel found on the Isle of Man and built between the 6th and 12th centuries. Some similar sites have been identified on Islay and Gallarus Oratory.
The earliest versions of the structures are all thought to have been lost, and only their later replacements (mostly in use between the 8th and 12th centuries) survive. These survivors vary in size and arrangement, and include examples constructed in unhewn or roughly worked stones, stone-revetted turf and timber-laced rubble. Beneath some sites remnants of clay daub have been found (Megaw 1978:298), while traces of wall plaster have also been discovered. Keeills may have fallen out of use following the arrival of Viking settlers on the Island, but were then re-established, on the same sites in some cases, once the Vikings had converted to Christianity.
A number of keeills were built on a natural or artificial mound, often the site of earlier burials or monuments (e.g. Bronze-Age barrow mounds) (Lowe and Reilly 1988) and/or near a spring or holy well (a chibbyr). Many keeills are surrounded by cemeteries, some of which may have originated in pagan society. Some keeills are enclosed by a turf bank. The area of ground bounded by such a bank can vary considerably and may represent earlier, pre-Christian use.