Per capita is a Latin prepositional phrase: per (preposition, taking the accusative case, meaning âby, by means ofâ) and capita (accusative plural of the noun caput, âheadâ).The phrase thus means âby headsâ or âfor each headâ, i.e., per individual/person.The term is used in a wide variety of social sciences and statistical research contexts, including government statistics, economic indicators, and built environment studies.he phrase thus means âby headsâ or âfor each headâ, i.e., per individual/person. The term is used in a wide variety of social sciences and statistical research contexts, including government statistics, economic indicators, and built environment studies.
Medical Definition of trichromatism. 1  1: the quality or state of being trichromatic. 2  2: color vision based on the perception of three primary colors and especially red, green and blueâcompare deuteranomaly, protanomaly.
Astigmatism is a vision condition that causes blurred vision due either to the irregular shape of the cornea, the clear front cover of the eye, or sometimes the curvature of the lens inside the eye.n irregular shaped cornea or lens prevents light from focusing properly on the retina, the light sensitive surface at the back of the eye. As a result, vision becomes blurred at any distance. Astigmatism is a very common vision condition. Most people have some degree of astigmatism.