anomaly vs unusual object

anomaly

noun
  • Any of various angular distances. 

  • A defect or malformation. 

  • A failure of a classical symmetry due to quantum corrections. 

  • Any event or measurement that is out of the ordinary regardless of whether it is exceptional or not. 

  • Something or someone that is strange or unusual. 

  • A deviation from a rule or from what is regarded as normal; an outlier. 

unusual object

How often have the words anomaly and unusual object occurred in a corpus of books? (source: Google Ngram Viewer )