yes

when an operator operate on a function and same function is reproduced with some numerical value then the function is called eigenfunction and the numerical value is called eigen value.

George H. Pimbley has written:

'Eigenfunction branches of nonlinear operators, and their bifurcations' -- subject(s): Nonlinear operators

E. C. Titchmarsh has written:

'Eigenfunction expansions associated with second-order differential equations' -- subject(s): Boundary value problems, Differential equations, Eigenfunction expansions, Harmonic analysis, Infinite Series

'The theory of the Riemann zeta-function' -- subject(s): Zeta Functions

'Introduction to the theory of Fourier integrals' -- subject(s): Fourier series

'The zeta-function of Riemann' -- subject(s): Zeta Functions