Definition of overfitting in US English:

overfitting

noun

Statistics
  • The production of an analysis which corresponds too closely or exactly to a particular set of data, and may therefore fail to fit additional data or predict future observations reliably.

Origin

1930s; earliest use found in Quarterly Review of Biology. From over- + fitting.

Pronunciation

overfitting

/ˌəʊvəˈfɪtɪŋ/