Verified answer

이모 (maternal) aunt, one's mother's sister

숙모 aunt, the wife of one's father's younger brother

외숙모 aunt, maternal uncle's wife, wife of one's mother's brother

고모 (paternal) aunt, one's father's sister

이모부 uncle, husband of one's aunt[mother's sister]

고모부 uncle, husband of one's aunt[father's sister]

당고모 an aunt (who is one´s father´s cousin)

시고모 an aunt on one´s husband´s side

넛할머니 one´s father´s maternal aunt, a great-[grand-]aunt on one´s father´s maternal side

시고모부 the husband of an aunt on one´s husband´s side

백모 an aunt, the wife of one´s father´s elder brother

작은어머니 an aunt, the wife of one´s father´s younger brother

큰어머니 an aunt, the wife of the elder brother of one´s father

삼촌댁 (숙모) the wife of one´s uncle, an aunt

here's one explanation which I found extremely helpful: http://thekoreanway.wordpress.com/2010/05/13/the-c...

and this one is fun if you watch K-dramas http://belectricground.com/2011/07/08/korean-langu... .. in fact, it was because I could tell actor were speaking different words than the screen said (for instance, "hyeong" instead of a man's name, "sunbae" instead of a student's name) that I began self-learning Korean. My own ancestral language names the grandparents by whether they are mother's side or father's side, too, and my cousins of course called my grandparents the opposite words.