The focus of something, such as a talk with a teacher, is the main reason for doing it or its central point.
eyeglasses having two focal lengths, one for near vision and the other for far vision
Belonging to,or concerning, a focus; as, a focal point.
being in focus or brought into focus; clearly delineated; -- of an image. Opposite of unfocused.
the concentration of attention or energy on something.
to concentrate attention or energy on something once more
spectacles that have three lenses for various ophthalmic conditions
Differentiated vocabulary for your students is just a click away.