Neo- \Ne"o-\ [Gr. ne`os youthful, new. See {New}.]
A prefix meaning new, recent, late; and in chemistry
designating specifically that variety of metameric
hydrocarbons which, when the name was applied, had been
recently classified, and in which at least one carbon atom is
connected directly with four other carbon atoms; --
contrasted with normal and iso-; as, neopentane; the
neoparaffins. Also used adjectively.
[1913 Webster]