The name Sinclair is of Scottish origin, derived from Saint-Clair, with "de" indicating the family's origins in Northumberland. It evolved over time into Sinclair and is associated with the powerful Highland clan that held extensive lands in Caithness and Sutherland. The name's meaning includes interpretations like 'clear' or 'bright', symbolizing purity or a clear mind/vision. Today, Sinclair remains popular as both a surname and given name worldwide, often used to evoke Scottish heritage.