The word does look like “Couson”.
Relationships on censuses aren’t always as expected, so keep an open mind. Some people would have known they are related but could be unsure exactly how. No proof would have been needed when completing the census forrm. Maybe cousin = nephew or niece? I’ve come across similar anomalies before.
You could do some research about the two to try to determine if they are “real” cousins.
Do they appear together on any other census and if so what is the relationship said to be? If not together, trace tnem on other censuses as who they are living with may help determine their relationship.