Hypothesis: a tentative theory about the natural world; a concept that is not yet verified but that if true would explain certain facts or phenomena; "a scientific hypothesis that survives experimental testing becomes a scientific theory"; "he proposed a fresh theory of alkalis that later was accepted in chemical practices."
Key excerpts from from article:
However, even Darwin himself struggled with the fact that the fossil record failed to support his conclusions. ". . . Why, if species have descended from other species by fine gradations, do we not everywhere see innumerable transitional forms? . . . Why do we not find them embedded in countless numbers in the crust of the earth?" (Origin of Species, 1958 Masterpieces of Science edition, pp. 136-137).
". . . The number of intermediate varieties, which have formerly existed, [must] be truly enormous," he wrote. "Why then is not every geological formation and every stratum full of such intermediate links? Geology assuredly does not reveal any such finely graduated organic chain; and this, perhaps, is the most obvious and serious objection which can be urged against the theory [of evolution]" (Darwin, pp. 260-261).
Darwin acknowledged that the fossil record failed to support his conclusions. But, since he thought his theory obviously was the correct explanation for earth's many and varied forms of life, he and others thought it only a matter of time before fossilized missing links would be found to fill in the many gaps. His answer for the lack of fossil evidence to support his theory was that scientists hadn't looked long enough and hadn't looked in the right places. Eventually they would find the predicted fossil remains that would prove his view. "The explanation lies, I believe, in the extreme imperfection of the geological record," he wrote (p. 261).
He was convinced that later explorations and discoveries would fill in the abundant gaps where the transitional species on which his theory was based were missing. But now, a century and a half later, after literally hundreds of thousands of fossil plants and animals have been discovered and cataloged and with few corners of the globe unexplored, what does the fossil record show?
Niles Eldredge, curator in the department of invertebrates at the American Museum of Natural History and adjunct professor at the City University of New York, is another vigorous supporter of evolution. But he finds himself forced to admit that the fossil record fails to support the traditional evolutionary view.
When the word "evolution" is invoked it's meaning is ambiguous to many people. It has multiple definitions. Darwin's being just one.
So depending on how you personally use and understand the word (evolution) and it's meanings it could be fact, theory, hypothesis, conjecture or none of the above.
"Darwin's original "theory" was a hypothesis. Latter disproved."
That's a creationist fantasy. Evolution has one of the best track records in the history of science.
Here is a quiz for you. What major hominid fossils were known, say in 1859, when Darwin's work was published?
Can you give me an even approximate estimate?