  We give a description of definable sets $P=(p_1,..., p_m)$ in a free
non-abelian group $F$ and in a torsion-free non-elementary hyperbolic group $G$
that follows from our work on the Tarski problems. This answers Malcev's
question for $F$. As a corollary we show that proper non-cyclic subgroups of
$F$ and $G$ are not definable and prove Bestvina and Feighn's result that
definable subsets $P=(p)$ in a free group are either negligible or
co-negligible in their terminology.
