Webster's Revised Unabridged Dictionary · 1913

Interrogation

Interrogation , noun

[Latin interrogatio: compare French interrogation.]

1.
The act or process of interrogating or questioning; examination by questions; an instance of interrogating; inquiry.
2.
A question put; an inquiry.
3.
A point, mark, or sign, thus [?], indicating that the sentence with which it is connected is a question. It is used to express doubt, or to mark a query. Usually called a question mark; called also interrogation point.

In works printed in the Spanish language this mark is not only placed at the end of an interrogative sentence, but is also placed, inverted [as thus (i)], at the beginning.