focal point
1
4.4
- noun
- /ˈfoʊkəl pɔɪnt/
- Specialized
:
foco
- Incident radio-frequency waves bounce off the dish to a subreflector placed at the focal point of the parabola.
Examples
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Chromatic aberration occurs when a lens does not bend all wavelengths of light to the focal point.
Blog text (19) -
So the focal point of this lens is right about here.
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The parallel ray goes to the focal point on the other side.
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Again, the beam can either be tightly focused for high power density or diffused for lower power density simply by moving the handpiece towards or away from the surgical site or focal point.
Academic text (1995) -
Such sensors employ the same principle as whispering galleries in such buildings as the U.S. Capitol; these ellipsoid-shaped rooms enable the smallest sound made at one focal point to be clearly heard at the other focal point, many feet away.
Academic text (2010) -
A focused external laser beam created an optical trap that exerts a Hooke's law restoring force with a known force constant on a bead near its focal point.
Academic text (2002) -
The focus of the experiment was on how the light converges at the focal point of the lens.
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When parallel rays of light hit the lens, they meet at the focal point on the other side.
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The high-powered telescope uses a mirror that directs light to its focal point for clearer images.
Synonyms
68
5.1
The central point where light rays meet
Surface Forms
Morphology
The noun phrase combines 'focal' (relating to a focus or center) with 'point' (a specific position), so the meaning of a location where rays meet or a center of attention is directly derivable from the parts. This compositional pattern is common cross-linguistically and applies to both the literal optical sense and the figurative sense, so a B1 learner who knows the constituents would likely understand it.
Etymology
Focal point comes from how lenses and mirrors work. Rays of light are brought together to a single point at the focal spot, so the phrase means the exact place where the rays meet.