Birders in Canada and the United States refer to several families of long-legged wading birds in semi-aquatic ecosystems as waders.

[1] Elsewhere in the world, the word refers to what North Americans call a "shorebird", various families of the order Charadriiformes.

[1][2] In the past all of these families were classified in the order Ciconiiformes based on overall similarity in anatomy and ecology, as well as some molecular data.

[7] In some field guides, the families Gruidae (cranes) and Aramidae (limpkin) are also considered to be waders too.

However unlike the previously mentioned families, cranes and the limpkin were never thought to be closely related to the heron-like birds and have always been classified as members of the order Gruiformes.