from Wiktionary, Creative Commons Attribution/Share-Alike License
- v. To remove from a stack.
from the GNU version of the Collaborative International Dictionary of English
- transitive v. To remove, or take away, from a stack; to remove, as something constituting a stack.
from The Century Dictionary and Cyclopedia
- To remove from a stack; undo from a stacked position: as, to unstack hay; to unstack guns.
un- + stack (Wiktionary)