The act or process of combining; a combination or union of things.
From combine plus the suffix -ment (from Old French -ment, derived from Latin -mentum). This French-influenced suffix creates nouns indicating action or result, common in legal and formal English.
Old suffixes like '-ment' in 'combinement' show English's Norman heritage—we inherited French ways of naming actions when the Normans conquered England in 1066!
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