dictionary

ampulla - Latin, "flask." The segment of the mammalian oviduct, distal to the uterus and near the ovary, where fertilization takes place.

chorion - An extraembryonic membrane essential for gas exchange in amniote embryos. It is generated from trophoblast and extraembryonic mesoderm (somatopleure). The chorion adheres to the shell in birds and reptiles, allowing them the exchange of gases between the egg and the environment. It forms the embryonic/ fetal portion of the placenta in mammals.

decidua - The maternal portion of the placenta, made from the endometrium of the uterus.

morula - Latin, "mulberry." Vertegrate embryo of 16-64 cells;, precedes the blastula or blastocyst stage. Mammalian morula occurs at the 16-cell stage, consists of a small group of internal cells (the inner cell mass) surrounded by a larger group of external (tropoblast) cells.

nodal vesicuar parcels (NVPs) - Small, membrane-bound particles in the mammalian embryo that contain sonic hedgehog protein and retinoic acid. Secreted from the node cells under the influence of FGF signals, Ciliary flow carries the NVPs to the left side of the body, delivering paracrine factors for the establishment of left-right asymmetry.

paralogues - Each member of a gene family, which is homologous to the others (that is, their sequence similarities are due to descent from a common ancestor and are not the result of convergence for a particular function).

progenitor cells - Relatively undifferentiated cells that have the capacity to divide a few times before differentiating and, unlike stem cells, are not capable of unlimited self-renewal. They are sometimes called transitamplifying cells, since they divide while migrating. Both unipotent stem cells and progenitor cells have been called lineage-restricted cells, but progenitor cells are usually more differentiated than stem cells.

rhombomeres - Periodic swellings that divide the rhombencephalon into smaller compartments, ech with a different fate and different associated cranial nerve ganglia.

spina bifida - A congenital defect resulting from failure to close the posterior neuropore, the severity of which depends on how much of the spinal cord remains exposed.

trophoblast - The external cells of the early mammalian embryo (i.e., the morula and the blastocyst) that bind to the uterus. Trophoblast cells form the chorion (the embryonic portion of the placenta). Also called trophectoderm.


Reference:
Definitions from : Developmental Biology Ninth Edition by Scott F. Gilbert