In early medieval Scotland, a mormaer was the Gaelic name for a regional or provincial ruler, theoretically second only to the King of Scots, and the senior of a toisech (chieftain). Mormaers were equivalent to English earls or Continental counts, and the term is often translated into English as 'earl'.
The etymology is variously debated as "Great Steward" (incorporating Gaelic and Picto-Latin), or "Sea Lord" (perhaps defenders against Vikings). Historians do not know if the institution was Gaelic or Pictish. It is notable mormaer occurs only in the post-Pictish period, so it is difficult to sustain any argument for Pictish origins. There is also debate whether mormaer was simply the east-coast equivalent of kinglet (Gaelic: ruirí or rí). For the earliest periods, there is uncertainty about the exact difference between a mormaer and a toisech (Modern Scottish Gaelic tòiseach 'chief'). The earliest Scottish Latin sources use thanus (thane) for toisech. This word was adopted from the Anglo-Saxon lands to the south. It is possible thanus, comes, mormaer and toisech all originally meant similar things, or at least were not part of a stratified hierarchy.