law: Sale of Goods Act, 1930
  4. Sale and agreement to sell
  (1) A contract of sale of goods is a contract whereby the seller
  
  transfers or agrees to transfer the property in goods to the buyer for a price.
  
  There may be a contract of sale between one part-owner and another.
  (2) A contract of sale may be absolute or conditional.
  (3) Where under a contract of sale the property in the goods is
  
  transferred from the seller to the buyer, the contract is called a sale, but
  
  where the transfer of the property in the goods is to take place at a future
  
  time or subject to some condition thereafter to be fulfilled, the contract is
  
  called an agreement to sell.
  (4) An agreement to sell becomes a sale when the time elapses or
  
  the conditions are fulfilled subject to which the property in the goods is to be
  
  transferred.