The story
- Ancient Greek · derived from-άς
- English today-adic
Back-formation from monadic, etc., from Ancient Greek -άς (-ás) (genitive -άδος (-ádos)) + -ικός (-ikós) (English -ad + -ic). Compare related adicity and Latinate -ary. The algebraic sense is by analogy with p-adic, since ℤ₍ₚ₎ equipped with the (p)-adic topology passes to the ring of p-adic numbers under the operation of completion.
Etymology from Wiktionary, CC BY-SA 4.0.