Is it correct to say, "Everyone brought their partner to the party."?
"Everyone" is singular so strictly speaking your sentence is incorrect. The most correct sentence would be with 'his or her partner', but this is a bit cumbersome so people usually say 'Everyone brought their partner to the party.'
If you say 'partners', it sounds like each person may have more than one partner.
Thank you, 2006. Your thread is most helpful.