It is important to know the difference between ordinary concentration and meditation. By the word ‘meditation’ we mean dhyana or contemplation. It is not just ordinary concentration. It is a special type of concentration. In the first place, meditation is a fully conscious process, an exercise of the will. Secondly, meditation means concentration on a spiritual idea which presupposes that the aspirant is capable of rising above worldly ideas. And finally, meditation is done usually at a particular centre of consciousness. It is clear that true meditation is a fairly advanced state, attained after long practice. It is the result of long years of discipline.

What is ordinarily known as meditation does not deserve the name. The mind is upset by various evil thoughts and tendencies, and worldly matters turn the mind away from the contemplation of God. To attempt time and again to draw the mind inward and fix it on God is the case with the majority of spiritual aspirants. Such a state is usually styled meditation. Really, it is pratyahara, withdrawing the outgoing mind; To keep the mind in the contemplation of the same thought for a short space of time is the next stage called dharana. When the outgoing tendencies are controlled and the mind flows continuously as a current in the contemplation of God, it is real meditation or dhyana.

Source: Meditation and Spiritual Life by Swami Yatiswarananda