The etymology of Late Latin Scoti is unclear. It is not a Latin derivation, nor does it correspond to any known Goidelic (Gaelic) term the Gaels used to name themselves as a whole or a constituent population-group. The implication is that this Late Latin word rendered a Primitive Irish term for a social grouping, occupation or activity, and only later became an ethnonym. Several derivations have been conjectured but none has gained general acceptance in mainstream scholarship. In the 19th century Aonghas MacCoinnich proposed that Scoti came from Gaelic sgaothaich, meaning "crowd" or "horde". Charles Oman derived it from Gaelic scuit, meaning someone cut-off. He believed it referred to bands of outcast Gaelic raiders, suggesting that the Scots were to the Gaels what the Vikings were to the Norse. More recently, scholars have speculated the likelihood of a group of raiders adopting a name from an Indo-European root, *skot, citing the parallel in Greek skotos (σκότος), meaning "darkness, gloom".