The stash in Lioneye's Watch.
The Stash is a bigger inventory, accessible by all characters you have in the same league. The Stash is located in each of the game's towns.
Items in the stash are separated by league, meaning a character in the default league can't access the stash from the hardcore league and so on. Once a character on a hardcore league dies, and he is sent to the default league, his stash tabs will appear as remove-only so you can retrieve your items from the hardcore league.
The default number of stash tabs is four and more stash tabs can be bought though microtransactions. The price for each new tab is 30 credits (USD 3.00) and the maximum number of tabs is over 64,000. Purchased stash tabs are global to the account, meaning they will appear on your stash no matter what league your character is currently in.
GGG currently have plans to include microtransactions for public stash tabs, which other people can see, and nameable stash tabs [1]