Multi Value field has the CHILD values from a child BC for the PARENT record configured through MVL. SINGLE value field will be either from the base table or joined table.

The Difference between Single Value Field (SVF) and Multi Value Field(MVF)
SVF- a field in BC which references a column in a table.
MVF- a field in parent BC which references a field in child BC.
Field-Identifies and defines a field in a business component. All fields making up a business component record contain entries from both Single Value Field and Multi Value Field object types.

Multi Value field has the child values from a child BC for the parent record configured through MVL. single value field will be either from the base table or joined table.

The Difference between Single Value Field (SVF) and Multi Value Field(MVF)
SVF- a field in BC which references a column in a table.
MVF- a field in parent BC which references a field in child BC.
Field-Identifies and defines a field in a business component. All fields making up a business component record contain entries from both Single Value Field and Multi Value Field object types.