periwinkle

(also winkle) n any of several types of small edible shellfish shaped like a snail 滨螺.

periodical, periodicity, peripatetic, peripatetically, peripheral, peripherally, periphery, periphrasis, periphrastic, periphrastically, periscope, periscopic, perish, perishable, perishables, perished, perisher, perishing, peristyle, peritonitis, perjure, perjurer, perjury, perk, perkily, perkiness, perky, perm, permafrost, permanence, permanency, permanent, permanent wave, permanent way, permanently, permanganate, permeability, permeable, permeate, permeation,