Floating point number A floating-point number represents a limited-precision rational number that may have a fractional part. ODM2 Property Data Type Controlled Vocabulary ODM2 Working Group A vocabulary for describing the data type for an extension property in ODM2. Extension properties can be added to many of the entities in ODM2 (e.g., Sites, Variables, etc.). The values of these extension properties must be of one of the listed primitive data types.