Added 9 October 2026 pia noun Categories: PlantsRare Words noun ! Definition from WordNet 3.1, Princeton University. More about pia at Wordnik → Where our words come from → Perennial herb of East Indies to Polynesia and Australia; cultivated for its large edible root yielding Otaheite arrowroot starch. Related Words: piousmaterepamrsevaluationassessmentiapairlinevet Back to today's word