Riddle - a puzzling problem or question, or an enigmatic saying or speech. The term also applies to a statement or query so phrased as to require ingenuity in discovering its meaning.
The term is from the Anglo-Saxon roedels derived from roedan, meaning “to read.”
This literary form existed during Greek and Roman times and the Middle Ages.
In Sophocles’s The Oedipus Trilogy (line 1524), King Oedipus of Thebes solved the most famous riddle—that of the Sphinx:
What goes on four feet, on two feet, and three
But the more feet it goes on, the weaker is he?
The answer is a man, who as an infant crawls upon all fours, as an adult walks erect on his own two feet, and in old age supports his tottering legs with a staff (the third leg).