NUMA stands for Non-Uniform Memory Access. It is a computer memory design used in multiprocessing systems, where the memory access time depends on the memory location relative to the processor. Under NUMA, a processor can access its own local memory faster than non-local memory (memory local to another processor or memory shared between processors)

This design helps improve the performance of systems with multiple processors by reducing the time it takes for a processor to access memory. It is commonly used in high-performance computing environments and can be beneficial for SQL Server configurations to optimise parallel processing and resource allocation.

CODE:

SELECT
    mn.processor_group
    , mn.memory_node_id
    , n.node_id AS cpu_node_id
    , n.online_scheduler_count
    , n.cpu_affinity_mask
    , n.online_scheduler_mask
FROM sys.dm_os_memory_nodes AS mn
INNER JOIN sys.dm_os_nodes AS n
    ON mn.memory_node_id = n.memory_node_id;

https://www.sqlskills.com/blogs/jonathan/category/numa/

From my SQL Server DBA handbook.