sə̇ˈnēdrə, sə̇ˈned-, ˈsinəd- noun
Usage: capitalized
Etymology: New Latin, from Greek synedros sitting together, from syn- + -edros (from hedra seat) — more at sit
: a large genus related to Fragilaria and comprising elongated linear or commonly needle-shaped solitary or loosely colonial diatoms that may cause earthy odors in water supplies