Definition of "fertile"

Of land, etc.: capable of growing abundant crops; productive.  examples

(figuratively) Of one's imagination, etc.: active, productive, prolific.  examples

(biology)

1. Capable of reproducing; fecund, fruitful.  examples

2. Capable of developing past the egg stage.  examples

(physics) Not itself fissile, but able to be converted into a fissile material by irradiation in a reactor.  examples