There isn't a scientific definition for "observation." In the Copenhagen interpretation, it really is treated just as vaguely as the colloquial definition, something the physicist John Bell complained about in his article "Against 'Measurement'", that the textbook axioms of quantum mechanics are inherently vague because they refer to "observation" or "measurement" which is not itself defined in the axioms. Saying that observation is just "when the wavefunction collapses" is a circular definition and doesn't answer anything, because then we can just ask, "when does the wavefunction collapse?" and the only answer the textbook axioms give is "when you observe/measure it."