id., idem=The same.
I.D.B. Illicit Diamond Buyer (in Cape Colony).
I.D.N., in Dei nomine=In the name of God.
i.e., id est=That is.
i.h.p. Indicated horse-power.
I.H.S., for the Greek capitals IHC, (the C a form of Greek Σ), the first three letters of the name Jesus, often misread as Jesus Hominum Salvator=Jesus Saviour of Men.
Ill. Illinois.
ill. Illustration, Illustrated.
I.L.P. Independent Labour Party.
Imp. Imperial; Imperator=Emperor.