Equipollent is an adjective that means equal in power and effect.

The Latin word pollere (poe LARE ay) means ‘to be strong.’ Our word of the day combines that with the prefix E-Q-U-I, which means ‘equally.’ When things or people are equipollent, they are equal in power. For example: The nations engaged in trade were not exactly equipollent. One was a third world country in desperate need of food. And the other was a wealthy empire.