(verb)
to surgically embed or insert something (either an artificial object or living tissue) in the body of a person or animal, or to become embedded in something (especially an embryo becoming embedded in the wall of the uterus);
e.g. She underwent a procedure to implant a pellet of medication into her arm.
(verb)
to introduce or establish something (typically an idea) in a person's mind;
e.g. You must try to implant this idea in his head.
(noun)
something that is inserted or transplanted into something else (especially into someone's body), such as a prosthetic device or a piece of tissue;
e.g. He wears an implant in his weak ear so that he can hear better.