  A classification of N-partite states, based on K-way negativities (K=2 to N),
is proposed. The K-way partial transpose with respect to a subsystem is defined
so as to shift the focus to K-way coherences instead of K subsystems of the
composite system. For an N-partite system, the fraction of K-way negativity
contributing to global negativity, is obtained. After minimizing K-way
negativities through local unitary qubit rotations, a combined analysis of
2-way, 3-way and global negativities is shown to provide distinct measures of
genuine tripartite, W-state like and bipartite entanglement, for three qubit
composite system. To illustrate the point, entanglement of three qubit GHZ
class states, W-class states, three boson state and noisy states is analysed.
While genuine N-partite entanglement of a composite system is generated by
N-way coherences, N-partite entanglement in general can be present due to
(K<N)-way coherences as well.
