Sentence:  <WSD>Analytic continuation</WSD> is a technique to extend the domain of a given analytic function. <WSD>Analytic continuation</WSD> often succeeds in defining further values of a function, for example, in a new region where an infinite series representation in terms of which it is initially defined becomes divergent. 
Meaning of the word marked with <WSD> tags:  The practice of extending analytic functions.