What Are Consumer ,predator, Prey And Producer?

A producer = plant - consumer = something that eats the producer - prey = something that usually eats the consumer but then gets eaten by the predator - predator = something that eats the prey  Eg:
 
producer = grass   grass gets eaten by the worm
consumer = worm   worm gets eaten by the bird
prey = bird   bird gets eaten by the fox
predator = fox