As I do some research on the history of speciation theories, I came across this, which is perhaps the original coining of the term:
Evolution is a process of organic change and development, universal and continuous, and due to causes resident in species. Speciation, to give the other process a name, is the origination or multiplication of species by subdivision, usually, if not always, as a result of environmental incidents. Speciation is thus an occasional phenomenon which does not cause evolution, and is not caused by evolution. One procession of organisms may be divided into two, but it does not appear that the new groups will travel in any different manner than before, nor that they will go any faster or any farther than if they had not been separated. The subdivision enables the two parts to follow different roads and to arrive at different destinations, but it does not assist the evolutionary locomotion nor give us any clue as to how it is accomplished. The evolutionary interest of isolation is that each case affords additional evidence of continuous, progressive change as the normal evolutionary condition of all groups of interbreeding organisms. The isolation of a new group is an interesting biological event, a crisis, as it were, in speciation, but it gives us no special opportunities of studying the causes of evolution. [Cook 1906:506]
By 1939, a Society for the Study of Speciation had been set up, although it lasted only a few years (Cain 2000). The 35 years following Cook’s paper were a frenzy of studies, theories and arguments.
Cain, Joe. 2000. “Towards a ‘Greater Degree of Integration’: The Society for the Study of Speciation, 1939-41.” The British Journal for the History of Science 33 (1):85-108.
Cook, O. F. 1906. “Factors of Species-Formation.” Science 23 (587):506-507.