a paste made from fish or small shrimps that are salted and fermented for several weeks
The liquid byproduct is drawn off and used as a sauce called patis.
Different areas of the Philippines have their own version of bagoóng. For example, the Ilocos region has its bagoóng terong, which is made with bonnetmouth fish. Another Ilocano bagoong is bugguong munamon, made from anchovies.
Other fish used are hairtail, roundscad and sardinella. Bagoóng alamang is a variant that uses small shrimps or krill as the main ingredient.
The Visayas region has guinamos, which is a thicker, denser version traditionally made by mashing the mixture with the feet (think of Italians crushing grapes by stomping on them).
Green, unripe mangoes (hilaw na mangga) are traditionally eaten with either salt or bagoóng.
Many Filipino soups and stews are flavored with bagoóng. Popular dishes that have it as an essential ingredient are dinengdeng and pakbet.
Binagoongan refers to a dish that heavily uses bagoóng for flavor. It is frequently a stew that uses pork as a main ingredient.