letter of intent

noun

a letter indicating that the writer has the serious intention of doing something, such as signing a contract in the circumstances specified. It does not constitute either a promise or a contract

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012