In his master’s steps he trod
Where the snow lay dinted
Heat was in the very sod
Which the Saint had printed
Good King Wenceslas by John Mason Neale
‘Sod’ is the ground, specifically pieces of ground with grass growing on it.
At primary school I didn’t know this and always thought it was great fun to sing this carol because there was a rude word in it. Of course, I wouldn’t be that childish these days.