Focus is a masculine noun meaning the sharpness of an image, the vision of a well-defined goal, the center and the point of convergence.
The expression "out of focus” indicates that the image is blurry, that it has gone out of the sharpening zone of a lens. Figuratively speaking, it is what is out of priority.
The expression "have focus” means having an objective, establishing a plan, being organized and having persistence to achieve the goals and achieve what is intended.
In the area of Physics, focus is a point where the light rays reflected by a mirror or refracted by a lens converge when the incident beam is of rays parallel to the optical axis.
In the area of Geometry, focus is the point of emanation of the vector rays for certain curves (ellipse, hyperbola, parabola, etc.).
Within the scope of Medicine, focus is the point of infection of certain microbial diseases, such as tuberculosis, among others. It's the place where pus forms, it's the focus of infection.
Still in the area of health
, focus is the place where the transmitting source of a disease is concentrated. For example: dengue outbreak – place where the accumulation of stagnant water is observed, which is the favorable environment for the creation of the mosquito that transmits the disease.