̈ɪˌpɪərɪˈɔdɪk adj. 1 appearing or occurring at
regular intervals. 2 of or
concerning the period of a
celestial body (periodic motion). 3 (of
diction etc.) expressed in periods (see PERIOD n. 7a). øperiodic
decimal Math. a set of figures repeated in a recurring decimal. periodic
function Math. a function returning to the
same value at regular intervals. periodic
table an
arrangement of elements in
order of increasing
atomic number and in
which elements of
similar chemical properties
appear at regular intervals. øøperiodicity n. [F p÷riodique or L periodicus f. Gk periodikos (as PERIOD)]