small number
finite number which is close in magnitude to 0
quadrillionth
name for the number 10⁻²⁴ or 10⁻¹⁵ depending on the scale used
billionth
reciprocal of 1,000,000,000
trillionth
reciprocal or ordinal of a trillion (in both meanings)
billionth
reciprocal of a billion (short scale) or of one thousand million (long scale)
millionth
1x10⁻⁶ in scientific notation