According to Nyaya, the classical Indian school of logic, the fallacy of the irregular middle is called

The fallacy of the irregular or inconclusive middle is Anaikantika (savyabhichara).

Here the middle term is not invariably tied to the major term.

The same mark is found both where the probandum holds and where it fails.

Such an erratic middle leads to no definite conclusion.

A wandering middle term that proves nothing certain is the Anaikantika hetvabhasa.