  We study the dynamics of surface homeomorphisms around isolated fixed points
whose Poincar\'{e}-Lefschetz index is not equal to 1. We construct a new
conjugacy invariant, which is a cyclic word on the alphabet $\{\ua, \ra, \da,
\la\}$. This invariant is a refinement of the P.-L. index. It can be seen as a
canonical decomposition of the dynamics into a finite number of sectors of
hyperbolic, elliptic or indifferent type. The contribution of each type of
sector to the P.-L. index is respectively -1/2, $+1/2$ and 0. The construction
of the invariant implies the existence of some canonical dynamical structures.
