Indeed it is. The OED cites William Whewell (1794-1866) in his work The Philosophy of the Inductive Sciences (1840):
"We need very much a name to describe a cultivator of science in general. I should incline to call him a Scientist." [Intro., p. 113]
In the same year, Blackwell's Magazine is also using the term, here at Vol XLVIII, p. 273:
Leonardo was mentally a seeker after truth -- a scientist; Corregio was an assertor of truth -- an artist.
The OED endeavours to give the earlist recorded occurance of a word; generally, words have been in at least limited spoken circulation for a time before making it into print. The first appearance in print is simply a measure of the point at which the term would generally have been understood, although in some instances (as perhaps in this current example, though the appearance in ~Blackwell's suggests the term was in more general circulation by 1840) it is indeed a proposal by an individual to introduce a new word.
Yes Patrick, thank you!
Natural languages (excluding deliberately-crafted artifacts such as Esperanto) undergo constant evolution in words, meanings and structures which may be analogous, in many particulars, to the processes described by biological evolution. The OED, cited in my previous post, gathers up something like the 'fossil record' of a language, the earlier variants of a word's orthography and semantics. From this record, it is clear that the meanings of words vary over time, often gradually, generally by small, incremental changes which are favoured by selective pressures.
Endless examples abound. To pick a personal hobby-horse, disinterested previously meant--and in the British Isles still primary means--"impartial, fair-minded, not having a personal stake in the outcome." In the United States, a colloquial usage arose whereby it was used as a synonym for "uninterested," which colloquial usage is becoming more widespread and it seems likely the use of 'disinterested' to mean 'impartial' will become extinct. This is descent with modification--but it is not random. It is not the case that on one particular date, the meaning of the word 'disinterested' suddenly mutated, far less 'randomly' mutated into a wholly unrelated meaning such as 'purple' or 'duct tape.' No one decided to change it, it changed through its changed usage being accepted by a growing number of speakers of English. It was 'selected,' in effect, without anyone doing the conscious selection.
That there are 'selective' processes on words does not mean that all words change meanings at the same rate. The verb "to be" has been under no evolutionary pressure to change in a thousand years--until your Mr. Clinton tried (and mercifully failed!) to challenge the meaning of the word "is"!
Linguistics, like biology, has nothing to say on abiogenesis, simply because we have no data at all on how language ever got started. But once started, the evolution of existing languages from earlier ones can be documented.
The analogy can be extended, but cutting to the chase: It would be easy to suppose, on casual examination, that a language--with its extensive vocabulary, shades of semantic nuance, extended rules of grammar--was too 'irreducibly complex' to be anything other than a designed artifact. But this is demonstrably false!
I'm wandering too far away from the topic here--I'll shut up now!
My reference, with specific citation, makes it ckear that the word science was used in its modern sense in 1725. That could imply the word was in common use by then.