Well, http://meriva.org states that
Meriva® is a patented formulation of curcumin, a dietary phenolic, with soy lecithin (non-GMO)(1). The two compounds form a non-covalent adduct in a 1:2 weight ratio, and two parts of microcrystalline cellulose are then added to improve formulation, with an overall contents of curcumin of 20%
A phytosome is
[...] a complex of a natural active ingredient and a phospholipid.
It is claimed that phytosome increases absorption of "conventional herbal extracts" or isolated active principles both topically as well as orally.
The complexation with phospholipid has been applied to many popular herbal extract or active molecules including [...] curcumin isolated from turmeric [...].
And Curcumin is
[...] is a diarylheptanoid. It is the principal curcuminoid of turmeric, which is a member of the ginger family (Zingiberaceae). Turmeric's other two curcuminoids are desmethoxycurcumin and bis-desmethoxycurcumin. The curcuminoids are natural phenols that are responsible for the yellow color of turmeric. Curcumin can exist in several tautomeric forms, including a 1,3-diketo form and two equivalent enol forms. The enol form is more energetically stable in the solid phase and in solution.
So, Meriva Phytosome Curcumin is a phytosome of curcumin developed by Meriva.