adjective
ChemistryDesignating a boron compound in whose molecules boron atoms occupy all vertices but one of a notional triangulated polyhedron; (also) designating the structure of such a compound. Chiefly (with hyphen) as a word-forming element. Compare "arachno", "closo".
Origin
1960s. From classical Latin nīdus nest + -o. Compare arachno, closo.
Are You Learning English? Here Are Our Top English Tips