Illegitimate – a child born to a couple outside of wedlock.

Immigrant – A person moving TO a new country.  (not to be confused with Emigrant)

Indenture – a contract between two parties, where one agrees to serve the other for a time in return for some type of repayment. 

Inheritance– Often, but not always the proceeds from a relation’s estate.

In-law – a person related by marriage to a sibling or offspring.  IE: Mother-in-law, Father-in-law, Sister-in-law, Brother-in-law.

Internment Camp – See Concentration Camp.

Issue – Offspring or children of a couple.  See also Progeny.