Definite articles el-la-lo in Spanish come from Latin demonstratives ille-illa-illud. Modern Spanish nouns have two gender system, masculine and feminine, and the neuter article can be used with many categories except nouns. Its main function is nominalization of the phrase. Definite articles el-la-lo share a same semantic feature [+definite] with which the speaker supposes that the referent is a known information to the hearer. Moreover, the neuter lo seems to have different semantic features from the other definite articles el-la. A large group of linguists argue that a main semantic feature of lo is [-individuation]. In particular, Bosque y Moreno(1990) classified possible interpretations of a phrase with lo in three types: entity, quality or quantity. According to them, in the case of referring to an entity, the neuter lo has [+individuative]. In my point of view, its general feature [-individuation] seems to conflict with one of its semantic sub-features [+individuative]. This article aims to resolve this problem by analyzing distinctive semantic features of the neuter lo in Spanish based on Cognitive Grammar. I propose that a distinctive semantic feature of the neuter lo is [-well delineated] while the other definite articles el-la have [+well delineated], because the speaker uses the neuter lo as pragmatic strategy characterized by subjectification.