A chine is a steep-sided river valley where the river flows through coastal cliffs to the sea. Typically these are soft eroding cliffs such as sandstone or clays. The word chine originates from the Saxon "Cinan" meaning a gap or yawn.

The word is in use in central southern England; in Hampshire, Dorset and particularly the Isle of Wight. In Dorset, west of Bournemouth is found Branksome Chine and Alum Chine, and east towards Boscombe, Honeycombe Chine. There are nineteen chines on the Isle of Wight including the popular tourist attraction Shanklin Chine. All chines are in a state of constant change due to erosion, and the most well-known example, Blackgang Chine, has been destroyed by landslides and coastal erosion during the 20th century.

Chines are the remains of ancient river valleys, now mostly small gullies leading down to the sea. As the walls of the chines and cliffs of the south coast of the Isle of Wight are so unstable and erode continually, the strata are clearly visible. Chines are therefore very important for their fossil records, their archaeology and the unique flora and fauna they provide shelter to.

There is also some fascinating folklore attached to the chines because of their history with local smuggling, fishing and shipwrecks. Shanklin Chine is also famous for its involvement in the Second World War, when it was used to carry one of the Operation Pluto pipelines and as training area for Royal Marine commandos before the 1942 Dieppe Raid.

Chines are very dependent on the farmed landscape around them because crops are typically grown right up to the edges of the chines themselves, and water drains into the chines from this farmland.