From YourAssociationWiki

1. The term batch pick refers to the combining of a group of order requirements by SKU into a single picking activity to optimize productivity by allowing one picker to select all the ordered merchandise within a predetermined group with one trip through the pick path. Batch picking requires subsequent mechanical or manual sorting of the merchandise to reestablish order integrity before shipping.^[1]
2. Batch picking may also refer to an order picker picking all the units of one item needed to satisfy a multiple of customer orders.^[2]

References

1. http://www.mhia.org/learning/glossary
2. http://www.bastiansolutions.com/resources/glossary-of-terms/default.asp