There often is confusion in applying the term to various classes of unfertilised eggs and
trophic eggs, depending on the area of expertise.
Virology In virology, eggs of domestic poultry are used for
culturing viruses for research purposes. Viruses generally can propagate only in live cells, so only a fertilised egg with a good supply of growing embryonic tissue is useful. Practitioners call such an egg
embryonated, as opposed to merely fertilised, because they're referring to an advanced stage of development, not merely after fertilisation.
Entomology In entomology, an egg sometimes is called unembryonated until it contains a visibly segmented embryo. An unembryonated egg might be a trophic egg, probably (but not necessarily) unfertilised or at least infertile. Such an egg will not contain a viable
zygote. Alternatively, "unembryonated" might refer to an egg that is "immature", not yet well into the process of development. These are likely to take a long time to hatch, as opposed to eggs that are laid partly
incubated and ready to hatch soon after, or even at the time of
oviposition. "Unembryonated" can also describe an empty shell, such as a
nit, the egg of a louse that has already hatched or has died. However, this usage is rarely described. Burgess (1995) states: "We have...come to reserve the term "nit" for the hatched and empty egg shell and refer to the developing embryonated egg as an "egg"".
Helminthology In
helminthology, the state of development of an egg is often relevant to particular phases of the life cycle; commonly the visible presence of an embryo is an important criterion for egg "maturity". Use of this definition of embryonated is common in certain scientific literature. For example: "...Immature eggs are discharged in the biliary ducts and in the stool. Eggs become embryonated in water". == References ==