Sections 4 to 23 contain definitions of terms that are used in the social security law.
Subsection 23(1) contains an entry for each expression that is defined for the purposes of this Act. That subsection is like a Dictionary.
The entry is either an actual definition of the expression or a signpost definition that identifies the provision that defines the expression.
Many other sections in this Part contain the actual definitions relating to a particular topic. For example, sections 4 and 5 contain family relationship definitions and section 8 contains income test definitions.