It's short for "etcetera", and it means "and so on", "and so forth", "and the like", "more of the same", and other such expressions used to denote non-exhaustive listings of related items.
"A computer has several major components. A CPU, hard disk, memory chips, video card, etc."
"Love, affection, food, water, etc. These are the things essential to life."
"I've been to many Asian countries. Japan, China, Korea, The Phillipines, etc."