What is a ceolmate?

Answer 1

There seem to be two possible interpretations of "ceolmate" which would be, either a misspelling of cellmate (a person who shares a cell) or a misspelling of soul-mate (an ideal mate).

Answer 2

A ceolmate is a term used in Old English to refer to a musical instrument, typically a stringed instrument like a harp or lyre. Ceolmate translates to "music comrade" in modern English.