A piece of grass-covered earth or turf, typically cut in rectangular pieces for laying lawns. In British slang, it can also be a mild profanity referring to a person.
From Middle Dutch 'sode' meaning turf or sod, related to 'seethe' through the notion of something that has 'settled' or 'sat'. The slang usage developed separately in British English as a euphemism.
The connection between grass and cursing might seem odd, but 'sod' as an expletive comes from 'sodomite', shortened and softened over time into a relatively mild British curse. Meanwhile, the grass meaning connects to our phrase 'sod's law' (similar to Murphy's Law), though this is likely coincidental wordplay rather than etymological connection.
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