UPDATE: 말코손바닥사슴 is the Korean word for "moose," not elk. The word is descriptive since 말코 means "horse nose" and 손바닥 means "palm," which most likely refers to the palm-shaped antlers of the moose. 사슴 means "deer."
The Korean word for elk seems to be 와피티사슴, which comes from the Korean transliteration of "wapiti" (와피티).
Photo of an elk from Wikipedia
By the way, can anyone count how many elk are in the following video?