Quotient is the result of division, kind of like how the result of addition is a sum, the result of subtraction is a difference, the result of multiplication is product.

math.fmod is the remainder of truncated divsion, not the remainder of floor division or modulo unlike the % operator so are you implying that math.fmod(-19, 12) returns 5 instead of -7?
Along with that, x % math.huge returns NaN (before Lua 5.3), math.fmod(x, math.huge) returns x.