Those elements which are equivalent in combining or displacing power to a single atom of hydrogen are said to be univalent or monad elements; whilst those which are equivalent to two atoms of hydrogen are termed bivalent or dyad elements; and those equivalent to three, four, five or six atoms of hydrogen triad, tetrad, pentad or hexad elements.   anvd [Please select]

Of these, one is called [Greek: pentadôron], the other [Greek: tetradôron].   anvd [Please select]

Public buildings are constructed of [Greek: pentadôra], private of [Greek: tetradôra].   anvd [Please select]