Literally, "ka-" means "co-" and "bayan" means "town". In the narrow sense, "kababayan" means a fellow from the same town or a townmate. However, it is often used in a much broader sense to mean countrymen or compatriots, especially by overseas Filipinos, OFWs, and connotes respect for each other’s commitment to unity because of their common cultural, political, and religious background from the same "bayan", broadly defined.
It should not be confused with balikbayan, a similar Filipino word, which refers exclusively to overseas Filipinos. "Balikbayan" oftens refers to (often wealthier) Filipinos who reside overseas and visit the Philippines periodically, even for extended stays, whereas "kababayan", when applied to overseas Filipinos, means ones that live in the Philippines but are overseas temporarily, even for years.
Kababayan is also the name of the Filipino-American club at UC Irvine. It has more than 400 members and is affiliated with Kaba Modern from MTV'S America's Best Dance Crew.
It is also the name of a kulintang-shaped muffin in the Philippines.