A humanoid (; from English human and -oid "resembling") is something that has an appearance resembling a human being. The earliest recorded use of the term, in 1870, referred to indigenous peoples in areas colonized by Europeans. By the 20th century, the term came to describe fossils which were morphologically similar, but not identical, to those of the human skeleton. Although this usage was common in the sciences for much of the 20th century, it is now considered rare. More generally, the term can refer to anything with uniquely human characteristics and/or adaptations, such as possessing opposable anterior forelimb-appendages (thumbs), visible spectrum-binocular vision (having two eyes), or biomechanic digitigrade-bipedalism (the ability to walk on heels in an upright position).