We don't have synonyms for field corn yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are field work, field coil and field john.
(n) :
(US) Any variety of corn (maize) grown primarily for fodder or use as grain; usually, one with lower sugar content than sweet corn and harvested either to be stored dry (on the cob or off, divorced of the stover) or ensiled along with the stover.
(n) :
(US) Any variety of corn (maize) grown primarily for fodder or use as grain; usually, one with lower sugar content than sweet corn and harvested either to be stored dry (on the cob or off, divorced of the stover) or ensiled along with the stover.