has_part has part has part develops_from develops from develops from existence starts with existence ends with animal zygote anatomical structure embryo stage embryonic structure conceptus embryo plus adnexa UMLS:C1516779 NCIT:C34131 UBERON:0004716 uberon EHDAA2 places this as a subtype of organism. This leads to the inference that a conceptus is an embryo (if an embryo is defined as an organism at embryo stage), which eliminates the embryonic + extra-embryonic = conceptus The embryo and its adnexa (appendages or adjunct parts) or associated membranes (i.e. the products of conception) The conceptus includes all structures that develop from the zygote, both embryonic and extraembryonic. It includes the embryo as well as the embryonic part of the placenta and its associated membranes - amnion, chorion (gestational sac), and yolk sac[WP]. BTO:0003834 Wikipedia:Conceptus EMAPA:36040 EHDAA2:0003235 AEO:0000194 EHDAA2:0000001 entire extraembryonic component