The name for Nintendo's Earthbound games in some markets. The first one (called Mother) was on Nintendo's 8-bit Famicom console and was not released outside of Japan, presumably because the developers had trouble rearranging the screen to account for the larger size in ROM of English text (most NES games were under half a megabyte). Mother 2, OTOH, was released as Earthbound on the SNES; it seems Nintendo had developed better i18n coding practices by then.

Also short for motherfucker.