Kalmar "decidua" tana nufin ƙwanƙwasa na musamman wanda ke layin mahaifa a lokacin daukar ciki kuma yana zubar da ciki lokacin haihuwa (tsarin haihuwa). An samo kalmar daga kalmar Latin "deciduus," wanda ke nufin "fadowa" ko "zubewa," yana nuna gaskiyar cewa an zubar da decidua bayan haihuwa da kuma mahaifa.
