Meditation was a planned skill category geared towards advancing in thaumaturgy. Investing in this skill would have improved the player's ability to recover focus, which should mean casting sustained powers will drain your focus at a lower rate. This would have benefited those who use thaumaturgy to achieve things for small durations of time such as improve their stamina recovery rate or slowly repair wounds. It may have also improved the length of time for which some offensive and defensive powers can be cast.
In March of 2019, the community manager confirmed that meditation was being removed and its planned skills merged with the other two remaining thaumaturgy-based skill categories - insight and concentration.