In mathematics, this is an integer that doesn’t divide another number into integral parts without leaving a remainder. For example, one can’t divide 16 by 5 without leaving a remainder of .2. In chemistry, an aliquant is a sample that’s divided into equal parts to leave a remainder.
The word’s first use as an adjective dates back to 1695, according to Merriam-Webster Dictionary. That book indicates that aliquant’s use as a noun started sometime around 1721. It is thought to be derived from Medieval Latin or New Latin “aliquantus”, which comes from the Latin words “alius” for some and “quantus” for how great or how much.