"Stands for Express Bus Terminal, mainly that of Seoul Gangnam Terminal." is "고터"(ko-tŏ) in Korean.
It stand for 고속터미널 (Express Bus Terminal). In youth words used in Seoul, primarily and Express Bus Terminal in Gangnam, it refers to the subway "Express Bus Terminal Station (고속터미널역)". The Gangnam Express Bus Terminal there is a large-scale underground shopping center.