A small admission. For many years, until quite recently, I thought that 'sematary' was just the American English spelling of 'cemetery'.
My elder brother's copy of the Stephen King novel Pet Sematary (pictured) was to blame.
As I understand, in the novel the sign for the pet cemetery is incorrectly spelt, having been written by children (the sign, that is, not the novel). The title of the novel refers to that incorrectly spelt sign. But how was I supposed to know that?
Especially as I would be more inclined to say 'graveyard' anyway...