Focal point and Vital principle

Focal point noun - A point of convergence of light (or other radiation) or a point from which it diverges.

Vital principle and focal point are semantically related In some cases you can use "Vital principle" instead a noun phrase "Focal point".

Vital principle noun - A hypothetical force to which the functions and qualities peculiar to living things are sometimes ascribed.

Focal point and vital principle are semantically related in center of activity topic. You can use "Focal point" instead a noun phrase "Vital principle".