Star Trek: 10 Things You Didn't Know About Gul Dukat
9. We May Never Know Dukat's First Name
Although fellow Cardassians such as Elim Garak, Enabran Tain, and Tekeny Ghemor all had the honour of a first name, this did not seem to be a courtesy extended to all members of this arrogant and militaristic race. Despite his prolific nature within the narrative of DS9, Dukat was never explicitly given a first name, although an innocuous log has resulted in widespread theory and discussion amongst fans.
Following the Cardassian recapture of Deep Space Nine, with its original title of Terok Nor restored, Dukat sits proudly in his new ready room, and takes the opportunity to record an entry in his 'Permanent Documentation File'. Commenting proudly on The Dominion's successes in the war effort, Dukat records the log under the title 'Dukat, S.G.', giving fans the first hints of a name beyond the imposing mononym.
Whilst some theorise that these initials refer to a rank such as 'Station Gul' or 'Supreme General', the non-canon novels have established the S as standing for 'Skrain', with fellow Cardassian Macet (also played by Alaimo) using the name to refer to a cousin, thus explaining the resemblance.
Whilst no canonical answer has ever been given as to what these initials stand for, or even mean, when pressed on the issue Ronald D. Moore has only ever given Dukat's name as Elmo. I guess that clears that one up then.