Sentence:  If f(x)\in\Z[x], the ring of polynomials with coefficients in \Z, then the "content of" f, denoted by c(f), is the greatest common divisor of the coefficients of f. The polynomial f(x) is called a <WSD>"primitive polynomial</WSD>" if c(f)=1. Since c(fg) = c(f)c(g), by Gauss's lemma [Hungerford, 74], the set S of <WSD>primitive polynomials</WSD> in \Z[x] is a multiplicatively closed set. Define \Lambda=\Z[x]_S, the localization of \Z[x] at S, a subring of the field of quotients \Q(x) of \Z[x]. Elements of \Lambda are of the form f(x)/g(x) with f(x), g(x)\in\Z[x] and g(x) a <WSD>primitive polynomial</WSD>. 
Meaning of the word marked with <WSD> tags:  A polynomial over an integral domain "R" such that no noninvertible element of "R" divides all its coefficients at once;  a polynomial over a GCD domain "R" such that the greatest common divisor of its coefficients equals 1.