Ma'anar ƙamus na kalmar "phytoplankton" ita ce: ƙananan halittu, masu iyo, masu kama da tsire-tsire waɗanda ke rayuwa a cikin ruwa, kamar teku, tafkuna, da koguna, kuma su ne tushen tsarin abinci na ruwa. Wadannan kwayoyin halitta ne unicellular da photosynthetic, ma'ana suna samar da nasu abincin ta hanyar amfani da hasken rana, carbon dioxide, da ruwa. Phytoplankton wani muhimmin sashi ne na yanayin yanayin teku, yana samar da fiye da rabin iskar oxygen da muke shaka kuma yana zama tushen abinci na farko ga yawancin dabbobin ruwa.