focus

Meanings

Noun

• A point at which reflected or refracted rays of light converge.
• A point of a conic at which rays reflected from a curve or surface converge.
• The fact of the convergence of light on the photographic medium.
• The quality of the convergence of light on the photographic medium.
• Concentration of attention.
• The exact point of where an earthquake occurs, in three dimensions (underneath the epicentre).
• The status of being the currently active element in a user interface, often indicated by a visual highlight.
• The most important word or phrase in a sentence or passage, or the one that imparts information.
• An object used in casting a magic spell.

Verb

• To concentrate during a task.
• To direct attention, effort, or energy to a particular audience or task.
• To cause (rays of light, etc) to converge at a single point.
• To adjust (a lens, an optical instrument) in order to position an image with respect to the focal plane.
• To concentrate one’s attention.
• To transfer the input focus to (a visual element), so that it receives subsequent input.

Origin

• Borrowed from Latin focus ("hearth, fireplace"); see there for more.