intersects:
if the intersection of both geometries is not empty
contains:
if the second geometry id completely contained into the first one
disjoint:
if the intersection of both geometries is the empty set
equals:
if they are spatially identical
touches:
if the only points in common between both geometries lie in the union of their boundaries
overlaps:
if the intersection of both geometries results in a value of the same dimension of both geometries and is different from both the first and the second geometry
within:
if the first geometry is completely contained into the second one
crosses:
if the intersection of both geometries results in a value whose dimension is less than the maximum dimension of both geometries and the intersection value includes points interior to both geometries, and the intersection value is not equal to either the first or the second geometry
References: