Someone is booking a flight for us, and they just sent us the code-laden reservation information:
Most of it I can figure out:
Cathay Pacific Airways Limited = The name of the airline, obv.
CX882 = The actual flight number
MO06JUL = Monday, July 6
HKG–LAX = Flight travels from Hong Kong to Los Angeles
DK1 = ??
1635 1455 = Local departure and arrival times
What is the DK1?
WAG: the seat number?
Googling tells me that’s a segment status code. There are a laundry list of those codes, and apparently different airlines have their own on top of the standard one.
The ‘1’ is how many seats you have, not clear on DK as I can’t find a specific reference.
Probably a fare category code.
Best I can figure from piecing together info from several sites is that DK = discount ticket, confirmed. Would that fit?
Ah. That could be it.
Back when I worked at a brokerage, DK meant “Don’t Know,” which means we have no record of this trade. Probably not used for airlines, tho.
When I worked for Eastern HK meant “holds confirmed”, HL was “holds waitlisted”. I can’t remember what DK is. Give me a minute.
ETA: I think it’s just another reservation system (not SystemOne) status for “holds confirmed”.
ETA2: It’s Amadeus’ reservation system code for “holds confirmed”.
/travel guru hat ON/
It means that the reservation is confirmed, as opposed to standby, waitlist, cancelled, etc.
/travel guru at OFF/
“Donkey Kong is your co-pilot.” 
When the agent wants to enquire a fare he has to book a sector in pnr temporarily. So when he sells the seat the sector status shows as DK1. It will s as good as a confirmed sector i.e. HK1. If he saves the pnr the DK changes to HK. That’s it. An agent will save only those sectors where passenger good ves him some assurity that he will buy the ticket from him. Hope this helps.
What’s a “sector”? A “sector status”? “Pnr”? “Confirmed sector”? What does DK and HK stand for?
The poster is probably not an American. Try this translation out of furrin airline worker speak into US traveler speak:
When the agent wants to check on a fare he has to book a specific flight between two cities against a specific named passenger. This is done within the passenger’s reservation record. The arbitrary code “DK1” means the seat space is temporarily removed from inventory, but the change(s) / addition(s) to the passenger’s reservation record have not yet been finalized.
If/when the reservation agent saves the individual passenger’s reservation record the DK1 changes to another arbitrary code: HK1 and the seat is semi-permanently removed from inventory. The agent will only save the changes after the passenger either buys the seat or promises to buy the seat. In many cases passengers have 48-72 hours to actually make the purchase; if not the reservation will be automatically cancelled and the seat returned to inventory.
From this we conclude the OP (whose trip was almost 2 years ago) got sent that info before everything was fully bought and paid for.
Yes, I too hate jargon-filled explanations. Even when I (mostly) know the jargon myself.