focus
UK[ˈfəʊkəs]US[ˈfoʊkəs]
n
the main or central point of something, especially of attention or interest
n
the point where rays of light, sound, etc. meet or from which they appear to spread
v
to give special attention to one particular person or thing, or to make people do this
Etymology
The word 'focus' was borrowed directly into English in the mid-17th century from Latin, where it meant 'fireplace' or 'hearth'. In Latin, the hearth was the central point of the home, the gathering place for the family. This concrete sense of a central point was extended metaphorically by the German astronomer Johannes Kepler in 1604. He used 'focus' to describe the point where rays of light meet after reflection or refraction, a pivotal concept in optics. From this scientific usage, the term broadened again in the 18th and 19th centuries to acquire its modern, abstract meanings related to a center of activity, attention, or clarity.
Analysis
The word 'focus' is a simplex loanword from Latin. It does not contain separable morphemes in its modern English spelling.
Examples
The main focus of the meeting will be on the new budget proposals.
Adjust the lens until the image comes into sharp focus.
You need to focus your efforts on finishing this report today.