What is the noun of tend?

The noun of "tend" depends on the meaning you're referring to. There are two main possibilities:

1. "Tend" meaning to take care of: The noun form is "tendance". This is a less common word, though, and you're more likely to see phrases like "care", "attention", or "maintenance".

2. "Tend" meaning to have a tendency to do something: The noun form is "tendency". This word refers to an inclination or predisposition towards a particular behavior or outcome.

So, the best noun form of "tend" depends on the specific context.