/ kəʊˈtɜːmɪnəs; NAmE koʊˈtɜːrm-/ adjective [ not usually before noun ] coterminous (with sth) ( formal )
1.
( of countries or areas ) sharing a border
2.
( of things or ideas ) having so much in common that they are almost the same as each other
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WORD ORIGIN
late 18th cent.: alteration of conterminous, with the same meaning.