Law of multiple proportion (Chem.), the generalization that when the same elements unite in more than one proportion, forming two or more different compounds, the higher proportions of the elements in such compounds are simple multiples of the lowest proportion, or the proportions are connected by some simple common factor; thus, iron and oxygen unite in the proportions FeO, Fe₂O₃, Fe₃O₄, in which compounds, considering the oxygen, 3 and 4 are simple multiplies of 1. Called also the Law of Dalton, from its discoverer. -- Multiple algebra, a branch of advanced mathematics that treats of operations upon units compounded of two or more unlike units. -- Multiple conjugation (Biol.), a coalescence of many cells (as where an indefinite number of amœboid cells flow together into a single mass) from which conjugation proper and even fertilization may have been evolved. -- Multiple fruits. (Bot.) See Collective fruit, under Collective. -- Multiple star (Astron.), several stars in close proximity, which appear to form a single system.

* A common multiple of two or more numbers contains each of them a number of times exactly; thus, 24 is a common multiple of 3 and 4. The least common multiple is the least number that will do this; thus, 12 is the least common multiple of 3 and 4.