What is "niekro"

Niekro is the surname of several people, most notably a family of American baseball players, all of whom have played in Major League Baseball:

• Phil Niekro (born 1939), pitcher; member of the Baseball Hall of Fame and younger brother of:
• Joe Niekro (1944–2006), pitcher; also father of:
• Lance Niekro (born 1979), first baseman