This value represents the amount of heat released when one mole of dimethyl ether is completely burned in oxygen under standard conditions (25°C and 1 atm pressure).

It's important to note that:

* Negative sign: The negative sign indicates that the reaction is exothermic, meaning heat is released during the combustion.

* Standard conditions: The heat of combustion is usually measured under standard conditions, but it can vary slightly depending on the specific conditions.

Let me know if you have any further questions about the combustion of dimethyl ether!