The quality or state of being grammatical; correctness according to grammatical rules.
English formation combining 'grammatical' with the suffix '-ness' (from Old English 'nes' meaning 'state or condition'), creating a synonym for 'grammaticality' with a more Germanic feel.
English gives us two ways to express the same idea—'grammaticality' sounds more like what scientists use, while 'grammaticalness' sounds more conversational, showing how English loves having multiple words for the same concept!
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