The informant is a dancer from Birmingham, Alabama. He has danced at home in Alabama and at school in Los Angeles and in both locations he’s encountered the word “merd”. Merd is something dancers say to wish each other good luck before a performance (similar to how actors say “break a leg”).
The informant gave background on the word. Apparently it comes from Louis XIV era France, when dancers would perform for the king. Horse-drawn carriages would arrive in a procession around the king’s palace, so naturally there was lots of horse poop on the streets. “Merd” is french for poop. So, the carriage drivers would warn, “merd!” when they arrived at the palace so that the dancers wouldn’t get their feet dirty.
I love the parallels between dance-folklore’s “merd” and theater-folklore’s “break a leg”. Both phrases are dirty and negative, but they really suggest well wishes and positivity. Like with most group folklore, it requires initiation in the group to understand the true meaning, since it differs so much from the literal meaning.