What do the following words have in common?

PI

MODE

GENE

NIT

PRO

LITE

 

HINT:

Each word can be followed by the same four letters to make new words.

Answer:

 

Each word can be followed by RATE to make a new word:

 

PIRATE

MODERATE

GENERATE

NITRATE

PRORATE

LITERATE

 

Credit:
Andrew Tyler (#1-3)