Anomaly is a noun.

A bumblebee is a physics anomaly that is able to fly when by its very design it should not. The Bumblebee is a large passive hairy bee that lives in small colonies underground.

F. Mezei has written:

'New experiments on giant zero bias tunneling anomaly' -- subject(s): Tunneling (Physics)

irregularity is the synonyms of anomaly

Anomaly means, essentially, irregularity. An example sentence would be: The anomaly of the necklace, is what she liked about it.