In scrum, an increment refers to the shippable product increment developed during the sprint. Increments are driven by definition of done.
Each increment is additive to the previous increments
In order to deliver value, the increment must be usable (shippable)
A sprint may produce multiple increments
The moment a product backlog item meets the ‘definition of done’ an increment is born.
An increment may be delivered to client even before the completion of the sprint