What is the difference between “Brothers” versus “Brethren”? When and how should they be used?

In the Grand Lodge of New York,

“Brethren” should always be used when referring to or addressing every Mason in the room, or every Mason who will receive a communication. “Brothers” should be used when referring to or addressing multiple Masons but not every Mason in the room or every Mason who will receive a communication. Thus, for example, the Master might call the Lodge’s attention to the Stewards by saying, “Brethren, give a round of applause to the Stewards. These Brothers did a great job with this evening’s collation.” In this case he uses “Brethren” to address his remarks to all those present, and then uses “Brothers” in his remarks to refer to the Stewards only.

The answers provided here reflect GLNY customs, rules, and ritual. We welcome discussion about how these may differ in your jurisdiction.