  The main aim of this paper is to study the growth of solutions of higher
order linear differential equations using the concepts of $(\alpha ,\beta
,\gamma )$-order and $(\alpha ,\beta ,\gamma )$-type. We obtain some results
which improve and generalize some previous results of Kinnunen \cite{13}, Long
et al. \cite{L} as well as Bela\"{\i}di \cite{b3}, \cite{b5}.
