Sentence:  The <WSD>"abc"-conjecture</WSD> of Masser and Oesterle is a typical example of a simple statement that can be used to unify and motivate many results in number theory, which otherwise would be scattered statements without a common link. 
Meaning of the word marked with <WSD> tags:  Given coprime positive integers "a", "b" and "c", such that "a" + "b" = "c", and "d" the radical of "abc" (the product of its distinct prime factors), the conjecture that "d" is usually not much smaller than "c" (in other words, that if "a" and "b" are divisible by large powers of primes, then "c" usually is not).