Invitational (adjective)

1. Relating to or being an invitation, or something that serves as an invitation.
2. Designed or intended to invite or attract attention or participation.

Origin:

Late 19th century from invite + -ational.

Examples:

1. It was an invitational tournament for the best golfers in the country.
2. The company sent out invitational emails to potential customers.
3. The invitational exhibition was open to all artists.
4. The invitational event was a huge success and attracted many participants.
5. The invitational atmosphere of the party made everyone feel welcome.