ˈfəukəs n. & v. --n. (pl. focuses or foci) 1
Physics a
the point at
which rays or waves meet
after reflection or
refraction. b the point
from which diverging rays or waves
appear to
proceed.
Also called
focal point. 2 a
Optics the point at which an
object must be situated
for an
image of it
given by a
lens or
mirror to be well defined (bring
into focus). b the adjustment of the
eye or a lens
necessary to
produce a
clear image (the
binoculars were not in focus). c a
state of clear
definition (the
photograph was out of focus). 3 the
centre of
interest or
activity (focus of attention). 4 Geom.
one of the points from which the distances to
any point of a given
curve are
connected by a
linear relation. 5
Med. the
principal site of an
infection or
other disease. 6 Geol. the
place of
origin of an
earthquake. --v. (focused, focusing or focussed, focussing) 1 tr.
bring into focus. 2 tr.
adjust the focus of (a lens, the eye, etc.). 3 tr. & intr. (often foll. by on)
concentrate or be concentrated
on. 4 intr. & tr.
converge or
make converge to a focus. øøfocuser n. [L, = hearth]
