A September 2025 executive order authorized the usage of "Department of War" as a secondary name. Department of Defense remains the legal name.
Even had the primary name legally changed the Department of Defense would still be the correct name of the organization at the time that @thisisnotauser worked for it.
Ya, it was kind of a tongue-in-cheek remark on my part. I don't agree with much of what this administration does, but I still think "Department of War" is more honest of a name for this institution.