Gabions (from Italian gabbione meaning "big cage"; from Italian gabbia and Latin cavea meaning "cage") are cages, cylinders, or boxes filled with soil or sand that are used in civil engineering, road building, and military applications. For erosion control caged riprap is used. For dams or foundation construction, cylindrical metal structures are used. In a military context, earth or sand-filled gabions are used to protect artillery crews from enemy fire.

Gabion baskets are wire mesh containers made from double twisted, hexagonal woven wire mesh. Once assembled, the baskets are filled on site with durable stone in order to create flexible, permeable, monolithic structures.

Gabions can be used to create:

- erosion protection structures

- weirs

- soil retaining walls (gravity and MSE)

- culvert headwalls

Gabion structures are able to develop and integrate with the surrounding environment, permitting the preservation or restoration of the natural environment. The filtering capability of the rock fill allows the soil, water, air, and plant life to interact naturally. Plant life can be developed even quicker by designing steps between each vertical layer creating planting shelves. As gabions provide a completely natural look, they have also used by architects as decorative elements of the landscape.