The genitive in languages like Czech, German, Japanese or Latin is notoriously multiply ambiguous. Some senses (partitive, possessive, relational, objective) are more or less well-studied, but one, in particular, is understudied: the explicative genitive (also called the genitive of apposition or of definition). I discuss this genitive across several languages and argue that it encodes the inverse of the function that the definite article is standardly taken to encode. Like the definite article, the explicative genitive (also: the EG) is polymorphic, taking arguments of a wide range of logical types. I further argue that many cases of apposition involve the EG meaning, more specifically, that so-called close apposition should be modeled in terms of a covert EG.