I. ˈfō-kəs noun
( plural fo·ci ˈfō-ˌsī also -ˌkī ; also fo·cus·es )
Etymology: New Latin, from Latin, hearth
Date: 1644
1.
a. : a point at which rays (as of light, heat, or sound) converge or from which they diverge or appear to diverge ; specifically : the point where the geometrical lines or their prolongations conforming to the rays diverging from or converging toward another point intersect and give rise to an image after reflection by a mirror or refraction by a lens or optical system
b. : a point of convergence of a beam of particles (as electrons)
2.
a. : focal length
b. : adjustment for distinct vision ; also : the area that may be seen distinctly or resolved into a clear image
c. : a state or condition permitting clear perception or understanding
tried to bring the issues into focus
d. : direction 6c
the team lost focus
3. : one of the fixed points that with the corresponding directrix defines a conic section
4. : a localized area of disease or the chief site of a generalized disease or infection
5.
a. : a center of activity, attraction, or attention
the focus of the meeting was drug abuse
b. : a point of concentration
6. : the place of origin of an earthquake or moonquake
7. : directed attention : emphasis
• fo·cus·less -ləs adjective
•
- in focus
- out of focus
II. verb
( fo·cused also fo·cussed ; fo·cus·ing also fo·cus·sing )
Date: 1775
transitive verb
1.
a. : to bring into focus
b. : to adjust the focus of (as the eye or a lens)
2. : to cause to be concentrated
focus ed their attention on the most urgent problems
3. : to bring (as light rays) to a focus : concentrate
intransitive verb
1. : to come to a focus : converge
2. : to adjust one's eye or a camera to a particular range
3. : to concentrate attention or effort
• fo·cus·able -kə-sə-bəl adjective
• fo·cus·er noun