What is meant by the term implantation and where does it occur?

Answer 1

When the sperm has met the egg, the egg journeys through the fallopian tubes, where it travels down into the uterus. Once it arrives into the uterus, it clings onto the walls, and tries to "implant" itself into the uterine lining. This is what is known as Implantation.

Implantation happens 5 to 9 days after conception. Once the egg has successfully implanted itself, the lining of the uterus sheds some blood. The blood travels down and presents itself 7 to 10 days after implantation. This is called implantation bleeding. By the time this spotting of blood reaches the outside, it has become "old" and thus looks black, brown, or dark red.

Not all women have implantation bleeding. Not having it does not necessarily mean your pregnancy is doomed or that you did not conceive that cycle. Most who experience this bleeding, naturally assume it is their period visiting days earlier than scheduled. Other than the light spotting, there are no other symptoms for implantation or implantation bleeding.

Hope that helped, I just copied it from another answer.