re-enforcement
/ˌriːɪnˈfɔːsm(ə)nt/noun
1The action or an act of re-enforcing.
2A person who or thing which re-enforces or strengthens; especially (frequently in plural) a person who or group which assists or strengthens a military force, etc.
Origin
Late 16th century; earliest use found in Raphael Holinshed (c1525–?1580), historian. From re- + enforcement, after re-enforce. Compare later reinforcement.