Definition

1. Noun:
   • A lens that causes a parallel beam of light to diverge or spread out: A concave lens is a transparent optical device, thinner at its center than at its edges, which causes incoming parallel rays of light to bend outward, making them appear to originate from a single point.

Usage

• A concave lens is used to correct certain vision problems, like nearsightedness (myopia).
• It is the opposite of a converging (convex) lens.
• It is often described as a .

Examples

• Noun:
  • A concave lens is used in the eyeglasses of a nearsighted person.
  • The flashlight used a concave lens to widen its beam.
  • In the diagram, the concave lens caused the light rays to spread apart.

Advanced Usage

• "To act as a concave lens": Used metaphorically to describe something that spreads out or diffuses focus, attention, or energy.
  • The new policy acted like a concave lens, dispersing the team's efforts instead of concentrating them.

Variants and Related Words

• Diverging lens: A direct synonym for a concave lens, emphasizing its function.
• Concave mirror: A related optical device with a reflective surface, but it converges light, unlike a concave lens which diverges it.
• Meniscus lens: A lens with one concave and one convex surface.

Synonyms

• Diverging lens: A lens that causes light rays to spread out.
• Negative lens: A term used in optics, referring to its negative focal length.

Related Phrases

• "Through a concave lens": Figuratively, to view something in a dispersed, widened, or less focused way.
  • He saw the complex issue through a concave lens, considering every peripheral factor.

Related Idioms

• None directly associated with the specific term "concave lens." However, the concept relates to idioms about perspective, such as "to look at something through a different lens."

Noun

1. a lens such that a parallel beam of light passing through it is caused to diverge or spread out