scientia

Scientia, scientiae, f., first declension, formed on the present participle of scio: literally the state of knowing. Classically it is knowledge or expertise in a particular thing and takes an objective genitive - scientia iuris, knowledge of the law.

The scholastics turned it into a technical term: a scientia is a demonstrative body of knowledge worked out from its own first principles, which is how it comes to mean "a science" and eventually the whole enterprise. Do not read the laboratory back into a medieval text. For Aquinas theology is the highest scientia and chemistry does not yet exist. Its companion is sapientia, wisdom, which judges what scientia merely knows. Conscientia, "knowing together with oneself", is the same noun with a prefix, and gives conscience and consciousness.