[MrRubix]

Most Chinese dialects do that (Mandarin, Cantonese, etc), and the word you're thinking of is "ma." In first tone, "ma1," it means "mother," but "ma3" (third tone) means "horse."

Just a different way of telling words apart. We don't have that kind of system in English. We might use one word for multiple things (such as "form" or "put" or "block" or "tip"), but we tell those words apart by their context. In Chinese, the WAY you say the word matters, too.