Category: O

Something which is seen wrongly so that it appears to be something else. A visual impression that is inaccurately perceived.  

An artificial fibre which can carry light or images.  

Same as optic. Relating to the visible light spectrum.  

Referring to the eye or to sight. Pertaining to vision or the orbit.  

A number which gives the strength of a person’s serum reaction to bacteria. A numerical measurement of the power of a person’s serum to attack invading bacteria and prepare them for destruction by phagocytes. It is measured by dividing the average number of bacteria in the blood per phagocyte in the presence of immune serum…

Hostility towards something. A movement of the hand muscles in which the tip of the thumb is made to touch the tip of another finger so as to hold something. The position of the thumb in relation to the other fingers when it is moved toward the palm of the hand. The ability to move…

Referring to a parasite or microorganism which takes advantage of the host’s weakened state to cause infection.  

One of a group of muscles which control the movements of the fingers, especially one which allows the thumb and little finger to come together. One of a group of muscles in the hand that bring the digits opposite to other digits. For example, the opponens pollicis is the principal muscle causing opposition of the…

A spasm of the body in which the spine is arched backwards, occurring, e.g., in people with tetanus. Severe muscle spasm, sometimes occurring in the final stages of tetany, in which the back arches, the head bends back, and the heels are flexed toward the back. The position of the body in which the head,…

What a person thinks about something.