Proto Indo-European *kista (woven container) led to Greek κιστή (woven basket, box), Latin
'cista' (woven basket, box) and modern Spanish cesta (woven basket). All of these words are
feminine, as is 'ciste' (chest), the Gaelic loanword from the Latin.
Old Irish had the terms 'céis' (piglet/sow), 'ceis/ceist' (horse-cloth) and 'ceis' meaning 'guidhe'
(prayer) or 'cuairt' (circuit). Also the feminine word 'ces' (woven basket / wickerwork coracle
or causeway / beehive), feminine 'ces' (spear) and 'ces' (debility).
Modern Irish has feminine 'céis' (a piglet or sow) and feminine 'ceis' (wickerwork such as a
basket or causeway). Modern Scottish has the feminine word 'céis' (case / hamper).
Medieval glosses present meanings for 'céis' in relation to the harp, often offering more than
one possible meaning, and as such they are very often guesses at the meaning of what is an
obsolete word from context. My first suggestion is that the word is related to 'ces'
(wickerwork) and is descriptive of the string gamut, and by extension, the harp itself.
'niro chelt céis Craiptini...
niro cheil Ros mac Find l^ Ferchertne fili céis ceól de cruit Crabtene'
he did not hide the céis of Craiphtine ...
Ros Mac Find, or Ferchertne (the) fili, did not hide céis music from Craiphtine's cruit
ni celt ceis ceol do chruitt Craiptini [majority reading]
(a?) céis did not conceal music from the cruit of Craiphtine
Ni cel do cruit ceol ceis Craiphtine [minority reading]
the music of (the?) céis of Craiphtine does not conceal from cruit, or,
the céis of Craiphtine does not conceal from cruit-music
céis ainm do chruith bic bís i comaitecht chruite móre
i.e. 'céis' (is) the name of a small cruit that accompanies a large cruit