Cell (from Lat. cella, probably from an Indo-European kal—seen in Lat. celare, to hide; another suggestion connects the word with Lat. cera, wax, taking the original meaning to refer to the honeycomb), in its earliest application a small detached room in a building, particularly a small monastic house (see Abbey), generally in the country, belonging to large conventual buildings, and intended for change of air for the monks, as well as places to reside in to look after the lands, vassals, &c. Thus Tynemouth was a cell to St Albans; Ashwell, Herts, to Westminster Abbey. The term was also used of the small sleeping apartments of the monks, or a small apartment used by the anchorite or hermit. This use still survives in the application to the small separate chambers in a prison (q.v.) in which prisoners are confined. The word is applied to various small compartments which build up a compound structure such as a honeycomb, to the minute compartments in a tissue, &c. More particularly the word is used, in electrical science, of the single constituent compartments of a voltaic battery (q.v.), and in biology of the living units of protoplasm of which plants and animals are composed (see Cytology).