How to delete a node label by command and api?

Question

Add label to nodes:

$ kubectl label nodes 10.xx.xx.xx key1=val1 

If I want to delete label(key1=val1) on node(10.xx.xx.xx), how

Answer 1

From kubectl label -h:

Update pod 'foo' by removing a label named 'bar' if it exists.
Does not require the --overwrite flag.
$ kubectl label pods foo bar-

The same works for nodes.