Convergence. When two are more organisms have the same shape, functionality, or organ, but are not said to have a close evolutionary ancestor, the organisms are said to have experienced convergence. It is used as a scientific-sounding term to hide evolutionary problems of similarities in unrelated organisms. The hope for evolutionists is that if there is a word associated with the problem, then there is no need to actually have evidence to show how the feature showed up, not just once, but many times throughout evolutionary history. An example of this would be that bats and dolphins use echolocation to eat, but they are not viewed as having a close evolutionary relationship.
To say that a shape, functionality, or organ evolved naturally even one time stretches the credibility/mathematics of reason, but to say that the same shape, functionality, or organ evolved multiple times in distinct and unrelated species is beyond belief.