enigma

n 1: something that baffles understanding and cannot be

explained; "how it got out is a mystery"; "it remains

one of nature's secrets" [syn: {mystery}, {secret}, {closed

book}]

2: a difficult problem [syn: {riddle}, {conundrum}, {brain-teaser}]

Enigma

The mechanical {cipher} engine used

by the Germans in World War II. Many of their messages were

deciphered at {Bletchley Park}, by {Alan Turing} and others.

(1995-03-25)