An expression of sorrow and/or concern for one's pet duck, who has recently come across some great misfortune.
Veterinarian: I'm sorry, Jack, but it looks like your duck won't make it through the night.
Jack: oh my duck.
Veterinarian: Yes, and we have strapped his bill closed to stop his wailing so as to reduce the complaints from the neighbors.
Jack: oh my duck.
guys in car with rubber duck on roof: heyyy girll
Taylor: hey man i like your duck.
guys in car with rubber duck on roof: yeahh, you wanna pet my duck?!
Taylor: ohh man, yeah i do!
Ashley: thats not what they meant...