noun
letter of invitation; invitation card
A formal written invitation, often for events like weddings, parties, or business functions. Typically includes details such as date, time, and venue.
結婚式の案内状が届いた。
I received a wedding invitation.
会社から忘年会の案内状が
I got an invitation from the company for the year-end party.
Compound of 案内 (guidance, information) and 状 (letter, document). The exact historical derivation is uncertain, but the word has been used since at least the early 20th century for formal invitations.