Ayatana
Āyatana (Pāli; Sanskrit) is a Buddhist term that has been translated as "sense base", "sense-media" or "sense sphere." In Buddhism, there are six internal sense bases (Pali: ajjhattikāni āyatanāni; also known as, "organs", "gates", "doors", "powers" or "roots") and six external sense bases (bāhirāni āyatanāni or "sense objects"; also known as vishaya or "domains"). Thus, there are six internal-external (organ-object) pairs of sense bases:
eye and visible objects
ear and sound
nose and odor
tongue and taste
body and touch
mind and mental objects
Buddhism and other Indian epistemologies identify six "senses" as opposed to the Western identification of five. In Buddhism, "mind" denotes an internal sense organ which interacts with sense objects that include sense impressions, feelings, perceptions and volition.
Saḷāyatana (Pāli; Skt. ṣaḍāyatana) refers to all six sense objects and six sense organs and is generally used in the context of the Twelve Causes (nidāna) of the chain of Dependent Origination.