Guests
Plus-One
An invitation that allows the guest to bring a date or partner.
A plus-one is offered to guests who are in a serious relationship (engaged, married, or cohabiting) and to wedding party members. It's traditionally not extended to all single guests, though that convention is loosening.
Name the plus-one on the envelope when you know it ('Sarah Chen and Marcus Lee'). Use 'and guest' only when the partner is genuinely unknown. Open plus-ones can inflate your headcount by 15-25%.