Is there a noun to express the property of a mathematical object being uni-, bi-, tri- etc. -variate? Maybe a weird question, but what is the best way to speak of the fact that a certain mathematical object can have the property of being uni-, bi-, tri- etc. -variate, if one wants to speak about it in general terms? Possible nouns could be 'Variability', which sounds not to hit the point of what wants to express, 'Variateness', which seems utterly uncommon in usage, or 'Variance', which I would prefer, but which has another well-known definition in statistics and may lead to confusion if used with another meaning. 'Variation' maybe? Or might there exist another suitable terminology, without referring to the 'varia' stem of the word?

The number of arguments for a function is called its arity.