Affixes

Examples include infrared, that part of the spectrum lying below visible light in frequency; infrastructure, the physical and organizational substructure or foundations (such as roads, buildings, and power supplies) needed for the operation of a society; infrasound, sound which is too low in frequency to be audible by human ears; infrarenal, lying below the kidney, and infraorbital, situated below the orbit of the eye, are two examples of a group of medical terms. Infra on its own is used in documents to refer to something further on in the text; infra dig, an abbreviation of Latin infra dignitatem, beneath (one's) dignity, is an informal term for something demeaning.