The name is a combination of a few things. From the official Square Enix blog:
In case you were wondering what the name of the DLC means, we’ll give you a hint: 3 Costumes, 3 Colosseums, 1 Dream and Date 119440927. As for what this means exactly, we’ll leave that up to you to figure out!
This covers the 3C3C1D part, however the date is left a mystery. Fortunately, this mystery has been solved.
From this Steam thread:
"09/27/11944", which is a date from a collaboration music video called "Deserving of Life" by Amasarashi. The date is directly referenced in the beginning
Here is the music video for "Deserving of Life" by amazarashi.