In Ojibwe  culture, a dreamcatcher (or dream catcher; Ojibwe asabikeshiinh, the inanimate form of the word for "spider" or bawaajige nagwaagan meaning "dream snare") is a handmade object based on a willow

Willow

Willows, sallows, and osiers form the genus Salix, around 400 species of deciduous trees and shrubs, found primarily on moist soils in cold and temperate regions of the Northern Hemisphere...

 hoop, on which is woven a loose net

Net (device)

A net, in its primary meaning, comprises fibers woven in a grid-like structure, and is very infrequently mentioned in discussions of philosophy. It blocks the passage of large items, while letting small items and fluids pass...

 or web

Spider web

A spider web, spiderweb, spider's web or cobweb is a device built by a spider out of proteinaceous spider silk extruded from its spinnerets....

. The dreamcatcher is then decorated with personal and sacred items such as feathers and beads.
While dreamcatchers originated in the Ojibwa

Ojibwa

The Ojibwe or Chippewa are among the largest groups of Native Americans–First Nations north of Mexico. They are divided between Canada and the United States. In Canada, they are the third-largest population among First Nations, surpassed only by Cree and Inuit...

 Nation, during the Pan-Indian Movement

Pan-Indianism

Pan-Indianism is a philosophy and movement promoting unity among different American Indian groups in the Americas regardless of tribal or local affiliations. The movement is largely associated with Native Americans in the United States, but has spread to other indigenous groups as well...

 of the 1960s and 1970s they were adopted by Native Americans of a number of different nations.