Czar and Co

Czar noun - A person of rank, power, or influence in a particular field.

Co and czar are semantically related In some cases you can use "Co" instead a noun "Czar".

Co noun - A hard ferromagnetic silver-white bivalent or trivalent metallic element; a trace element in plant and animal nutrition.

Czar and co are semantically related in leader of military or other organization topic. Sometimes you can use "Czar" instead a noun "Co".