(1) An unscientific field of study which later becomes a science.
(2) A field of study that has not yet been adequately tested or at the initial phase of the scientific method, involving information gathering and hypothesis formulation, but is not yet falsifiable, or if it is, its predictions have not yet been observed.
In protoscience, the theory may be consistent with existing science or which, where inconsistent, offers reasonable account of the inconsistency.
It may also refer to a historical philosophical discipline that existed prior to the development of scientific method, but later developed into a scientific discipline, for instance is alchemy that later became a legitimate science now known as chemistry.
Word origin: from Greek prôtos, meaning first + science. The philosopher of science Thomas Kuhn first used the word in an essay, originally published in 1970.