1. Within the hold of a vessel.

2. Within a ship or other vessel.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• inword,
• ezboard,
• onboards,
• abboard,
• lonboard,
• inbond,
• inbark,
• eboard,
• onbard,
• onbourd,
• inboad,
• oboard,
• inboud,
• mainboard,
• inheard,
• inard,
• onbord,
• antbord,
• inboaed,
• inboarde

• informant,
• aboard,
• invariant,
• informing,
• inpour,
• informed,
• invar,
• informal,
• infrared,
• inform,
• inborn,
• inpouring,
• infra,
• informer,
• infarct.

The adjective form of "inboard" is "inboard".

The plural form of the word "inboard" is "inboards"

The singular form of the word "inboard" is "inboard". The word does not change when going from singular to plural.