An eigenvector of a point-set is an eigenvector of the covariance matrix of the point-set. An eigenvalue of a point-set is an eigenvalue corresponding to an eigenvector of the point-set.
Pastel uses the PASTd algorithm to efficiently compute approximate eigenvectors and eigenvalues for point-sets.
Projection Approximation Subspace Tracking, Bin Yang, IEEE Transactions on Signal Processing, vol. 43, no.1, Jan. 1995.
Eigenstructure of the covariance matrix of a point-set