focus
pl. foci [L. focus, hearth]
1. The point of convergence of light rays or sound waves.
2. The starting point of a disease process.
There's more to see -- the rest of this topic is available only to subscribers.

pl. foci [L. focus, hearth]
1. The point of convergence of light rays or sound waves.
2. The starting point of a disease process.
There's more to see -- the rest of this topic is available only to subscribers.