The quality or state of being crosswise; the condition of lying, moving, or being oriented across something.
From 'crosswise' (adverb) combined with '-ness' suffix (from Old English '-nes'). A somewhat archaic formation following the English pattern of nominalizing adjectives and adverbs by adding '-ness'.
This word is almost extinct in modern English, which is fascinating—it suggests that by the 20th century, we stopped needing an abstract noun for 'the quality of being crosswise' because we could just say 'it's crosswise' or use more specific technical terms instead.
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