There is some debate as to whether these posts truly are linguistics lessons or simply etymology lessons. I contend, correctly of course, that etymology is a part of linguistics.
In any case, today we will be discussing the phrase "to pass muster."
Muster, it turns out, is a noun meaning "a gathering for inspection, review or roll call." And "muster roll" is a military term, not a type of nigiri sushi. Thus, the phrase "to pass muster" means to meet a required standard.