noun

1. a large pile of straw, hay, etc., esp. one neatly arranged, as in a conical form, for outdoor storage
2. any somewhat orderly pile or heap, as of boxes, books, poker chips, etc.
3. a number of arms, esp. three rifles, leaning against one another on end so as to form a pyramid
4. Brit. a unit of measure for firewood or coal, equal to 108 cubic feet
5. 1. a number of chimney flues or pipes arranged together
   2. smokestack
6. ☆
   1. an extensive series of bookshelves
   2. the main area where books are shelved in a library
7. 1. the part of a computer memory used to store data temporarily: retrieval of data from it is in reverse order to its storage
   2. the data so stored
8. Informal a large number or amount

Etymology: ME stac < ON stakkr, akin to MLowG stack, barrier of slanting stakes: for IE base see stick

transitive verb

1. to pile or arrange in a stack
2. to load with stacks of something
3. to assign (aircraft) to various altitudes for circling while awaiting a turn to land
4. to arrange in advance underhandedly so as to predetermine the outcome to stack a jury

intransitive verb