The main difference is: Memory coherence is for one memory location, while memory consistency defines what should happen for multiple locations.

So could I say that let f(L, m) := The order L makes all operations (read, write) on X consistent. Memory coherence: For each memory m, exists order L such that f(L, m) Memory consistency: Exists order L such that For each memory m, f(L, m) holds.

Memory coherence is due to a memory address being represented in multiple places (i.e. cache) and needs to be presented as one shared memory. Therefore, the result of operations on that address needs to appear as if it is a single shared address.

While memory consistency is due to multiple access (i.e. processors) to the entire memory (different addresses), and to ensure that each access gets the expected state of the memory.