Focality is an informative dimension of language which is expressed in the introduction of referential epicenters. Its study has given rise to extensive terminology for defining its functions and naming its various expressions and codification mechanisms. This profusion of terminology has been accompanied by important disagreements and by evident contradictions in the use of the most significant conceptualizations. Because it is a complex topic that has not been researched extensively, a systematization that will clarify part of the confusing terminology and that will organize the focal function according to its central, or best-known, aspects is suggested. The central components of the problem, illustrated and analyzed in a sample of Chilean Spanish, will be delimited by means of a critical review of relevant literature. The analysis will be carried out within the framework of functional principles and descriptors, an approach in which the informative functions of the clause are crucial. Among the most significant findings are the existence of a focal gradient in both the referential effects of the process and the organization and functioning of its most common forms of instantiation. Also worthy of note is the significant rote of the acoustic factor, which makes a far more important contribution to focus codification than what the literature indicates, white distinguishing focalization - related processes, such as thematization and topicalization.