That Wikipedia article does cite other ways of defining species, just after your quote. The bottom line is that there is no one correct and concise definition.

That Wikipedia article does cite other ways of defining species, just after your quote. The bottom line is that there is no one correct and concise definition. It's also obvious that the fertile offspring definition is not sufficient of you look at plants (pomelos, mandarins and citrons are rather obviously different species, but they are interfertile and most modern citrus species are their hybrids) or even more obviously, at bacteria or yeasts that don't even reproduce sexually.