Lim is short for Limit in mathematics.
The Lim bay and valley is a peculiar geographic feature found near Rovinj and Vrsar in Istria, Croatia, south of Poreč. The name comes from the Latin limes for "limit", referring to the landform's position at the border of two Roman provinces.
The Lim valley (Limska draga or Limska dolina) is 35 km long valley of the river Pazinčica. The Lim bay (Limski zaljev) is a 12 km long estuary.
The estuary is sometimes confused for a fjord. It isn't a fjord as it wasn't created by a glacier but by the river eroding the ground on its way into the Adriatic Sea. Due to its width it's also sometimes referred to as the Lim channel (Limski kanal).