noun

1. An ongoing relationship between (usually two) rivals who compete for superiority.

   “James and Polly have a bitter rivalry due to the latter's inclusion in the Tea Time Teaser.”

2. The characteristic of being a rivalrous good, such that it can be consumed or used by only one person at a time.

   “Common goods are those which are rivalrous in consumption but non-excludable”

3. Any competition between two or more things or factors.

   “Binocular rivalry is a visual phenomenon in which perception alternates between different images presented to each eye.”