Z

Zona drilling: The use of chemical to dissolve the gelatinous coating of the egg leaving a hole through which the sperm can enter. 

Zona Pellucida:  The transparent membrane or shell surrounding the oocyte (egg).

Zygote:  The cell formed as a result of fertilisation.

Zygote Intra-Fallopian Transfer (ZIFT):  The transfer of zygotes (early stage embryos) to the fallopian tubes for purposes of achieving a pregnancy. Embryos are transferred at the fertilised egg (one cell embryo) stage.