1) Acronym for "Oscillation Project with Emulsion-Racking Apparatus" an experiment at the LGNS facility in Italy
, an experiment known for promoting a sensational and clearly incorrect result that the neutrino
can travel faster than light.
2) Verb: to screw up
in an experimental or research context
3) Noun: an experimental error that should have been caught, but affected results.
4) to pull an OPERA. verb: to make an error when showing results; to engage in definition #3