You just taught me something I didn’t know - the “C” change referring to music!!
Sometimes when a word or phrase is used for years, correctly or incorrectly, it ends up in Webster’s Dictionary. Guess they quit fighting it, lol.
They do list ‘sea change’ as a transformation or something changed by the sea.
When a teenager in Galveston I felt a ‘sea change’ each time I swam in the ocean [Gulf]. Lying on your back and floating in the sunshine and comfort of the waves and you would feel a sense of peace and tranquility unmatched.
Just a memory that might not make sense to all.
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I could post a graphic.....