(mathematics) infinitesimal / infinitesimal (extremely small)

fundamental, basic

smallness; small size, small (sometimes used as an abbreviation for small serving, etc.) / Short for 小の月 (shō no tsuki).

concept, general idea

basis, foundation / (martial arts) kihon

goblin, ghost; an apparition

change in society, climate, or condition, transformation, variety / variation / declension / (sumo) a step to one side during the tachiai, the initial charge at the start of a sumo match; a sidestep

to change, to vary

(philosophy, general) infinity, unlimitedness, endlessness / (mathematics) infinity

unlimited, infinite, endless