Plural of gratter; tools or implements used for grating, scraping, or rendering; or people who grate.
From 'gratter' (one who grates), derived from the verb 'grate' plus the agent noun suffix '-er.' The double 't' appears in stressed syllables before the suffix.
A 'gratter' can be a tool or a person, which shows how English efficiently uses the same word for both the instrument and the agent—it's why we can say 'the cheese grater' but also 'the person grating the cheese.'
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