commutation
Concise Oxford English Dictionary © 2008 Oxford University Press:
commutation/kɒmjuˈteɪʃn/
▶noun
- 1 the action or process of commuting a judicial sentence or a legal obligation or entitlement.
- 2 the process of commutating an electric current.
- 3 Mathematics the property of having a commutative relation.
'commutation' also found in these Oxford entries:

