The story
The earliest known formulation of the theorem was in the Chinese Sun Zi's Mathematical Manual circa 400 AD.
Etymology from Wiktionary, CC BY-SA 4.0.
Chinese remainder theorem
Today it means: A theorem stating that, if one knows the remainders of the Euclidean division of an integer n by several integers, then one can determine uniquely the remainder of the division of n by the product of these integers, under the condition that the divisors are pairwise coprime. Full definition →