A buyer broker agreement is a contract with the buyer and the broker to work together for a specified time period to help the buyer find a property.
Posthumous [ a. - Born after the death of the father, or taken from the dead body of the mother; as, a posthumous son or daughter. - Published after the death of the author; as, posthumous works; a posthumous edition. - Being or continuing after one's death; as, a posthumous reputation. Meaning of 'posthumous' (Princeton's WordNet)
A conveyance of property, usually of an interest in land. Originally meant a posthumous grant but has come to be applied commonly to a conveyance that is made for a definitive term, such as an estate for a term of years. A lease is a common example, and demise is sometimes used synonymously with lease or let..