pickerelweed \ˈ ̷ ̷( ̷ ̷) ̷ ̷ˌ ̷ ̷\noun 1.: a plant of the genus Pontederia; especially: an American aquatic herb (P. cordata) growing in shallow water of streams and ponds and having spikes of blue flowers and cordate or sagittate leaves 2.: any of various still-water species of the genus Potamogeton