(1) For the crypto index fund protocol, see 
Set protocol.
(2) An internal DOS/Windows command that sets environment variables, which are stored values used by the operating system and many applications.  To display the current values, type:
      set
SETTING A VALUE
The 
set command creates an environment variable and places a value into it.  Blank spaces matter.  The following examples create NEWVAR with a value of "a."
  set newvar=a   create newvar with "a"
  set newvar= a  create newvar with " a"
  set newvar=    delete newvar
(2) (SET) (
Secure 
Electronic 
Transaction)  A standard protocol from MasterCard and Visa for securing online credit card payments via the Internet.  In this three-way transaction, the user, merchant and bank must use the SET protocols.
Credit card data and a digital certificate (for authentication) is stored in a plug-in to the user's Web browser.  The order is received by a SET-enabled merchant server that passes encrypted payment information to the bank.  Approval is electronically sent to the merchant.