Which term refers to the definite and obvious turning of the eyes from normal vision?

The term that denotes the definite and obvious turning of the eyes from normal vision is "tropia." It refers specifically to a condition where one eye is misaligned or turned in a consistent manner, making the misalignment clearly visible. In clinical practice, tropia is often assessed during an eye exam to determine how well the eyes work together.

In contrast, the other terms represent different aspects of eye alignment and movement. For example, phoria refers to a latent deviation that is not always apparent; the eye appears aligned until fixation is disrupted. Exotropia and hypertropia are specific types of tropia, with exotropia indicating an outward turn of the eye and hypertropia indicating an upward turn. While these terms are related to eye misalignment, tropia encompasses the general category of noticeable strabismus, making it the most appropriate answer for this question.