anatomical structure extraembryonic structure A multicellular anatomical structure that is associated with an embryo and derived from the zygote from which it develops, but which does not contribute to the embryo proper or to structures that are part of the same organism after embryogenesis. AAO:0010020 AEO:0000042 BILA:0000042 CALOHA:TS-2119 CARO:0000042 EHDAA2:0003042 EHDAA:46 FBbt:00005835 FMA:85537 HAO:0000042 TAO:0000020 TGMA:0001843 UBERON:0000478 UMLS:C1282438 VHOG:0000292 XAO:0004005 ZFA:0000020 extra-embryonic structure extraembryonic tissue see also conceptus extraembryonic component in EHDAA2. uberon