Cain bairns or kain bairns were infants who, according to Scottish superstition, were seized by warlocks and witches, and paid as a tax or tithe to the Devil.[1][2][3] Càin is a Gaelic word for a tribute, tax or tithe, and is the origin of the Lowland Scots term "kane",[4] while "bairn" means a child.[5]
The word was in use along the Scottish Borders, according to Walter Scott's Minstrelsy of the Scottish Border.[1]
It is unconnected with Cain in the Bible.