Definition of "upstaging"

present participle and gerund of upstage  examples

A situation where somebody or something is upstaged; thus:

1. (theater, also figurative) A stealing of the spotlight, as (or as if) one performer eclipses another in the audience's attention.  examples

2. (medicine, surgery, oncology) An increase in the stage of a case of a disease (usually a cancer), from a less-threatening to a more-threatening stage.