precedence

1. A designator, which indicates the order in which a number of messages shall be served. Four precedence levels are provided for SDS, with one being the highest and four the lowest. Messages with precedence level one are served first and those with level four last. These correspond to the four precedence levels, Flash, Immediate, Priority, and Routine respectively. 2. (Reconnaissance) A letter designation, assigned by a unit requesting several reconnaissance missions, to indicate the relative order of importance, within an established priority, of the mission requested.

The rules of conduct that, in the absence of other guidance, determine what should happen first. For example, in the absence of parentheses, you always do multiplication before addition.

In communications, a designation assigned to a message by the originator to indicate to communications personnel the relative order of handling and to the addressee the order in which the message is to be noted. [After JP1] Note: The descending order of precedence for military messages is FLASH, IMMEDIATE, PRIORITY, and ROUTINE.