Gaelic had all but disappeared as a language spoken natively in southern Fife by the mid-14th century, there is no continuous Gaelic tradition for the name, but the modern form is Innis Cheith.

Such a rocky and exposed island can however never have supported many trees so it would be reasonable that the derivation may be otherwise. Early associations between Saint Adomnán and the island may indicate that the second element is derived from the name of his contemporary and associate Coeddi (or Céti),