"Lectio Divina" is the particular way by which Catholics read the Scriptures. It is a reading of the Scriptures that seeks to encounter God through the sacramentality of the Word. As such, it is not mere understanding, it is "knowing" the Word of God in the spirit of prayer. It is in this way that the Catechism explains it as the first "wellspring of prayer" (nn. 2653-4)
The Church "forcefully and specially exhorts all the Christian faithful... to learn 'the surpassing knowledge of Jesus Christ' (Phil. 3:8) by frequent reading of the divine Scriptures... Let them remember, however, that prayer should accompany the reading of sacred Scripture so that a dialogue takes place between God and man. For 'we speak to him when we pray; we listen to Him when we read the divine oracles'.
In paragraph 2654, the Catechism puts the reading of Scriptures within the monastic tradition of the lectio:
The spiritual writers, paraphrasing Matthew 7:7, summarize in this way the dispositions of the heart nourished by the word of God in prayer: "Seek in reading and you will find in meditating; knock in mental prayer and it will be opened to you by contemplation.Reading must lead to meditation, meditation to prayer and prayer to contemplation -- the ladder of the lectio divina. Guy the Carthusian explains how the steps of this ladder lead from one to the other. Interesting is the process that he describes. One reads by pronouncing the words and listening to them. Meditation is understanding what the words or phrases mean. This is a slow process likened to the act of masticating that involves an internal dialogue between the reader and the author of the text about the text. Once the text is understood, one can now pray "from" the text: by petition, adoration, praise or thanksgiving. Finally, when the Holy Spirit allows it, the reader is given a glimpse of the mystery thus understood. This is the final stage of the reading: contemplation -- a glance into God Himself.