The Catholic Church celebrates the Solemnity of the Annunciation on March 25. This particular feast recalls the "announcement" of the angel Gabriel to the Blessed Virgin Mary, that she would bear Jesus Christ in her womb.
The word “annunciation” comes from the Latin name for the feast: (Annuntiationem Beatae Mariae Virginis). The word annuntiationem has at its root the Latin word annuntiare, meaning “to announce.”
While most are familiar with the Annunciation to the Blessed Virgin Mary, this word is also applied to the Annunciation to St. Joseph that occurs in the Bible.
This event is recorded in the Gospel of Matthew and tells how an angel "announced" the miraculous conception of Jesus in Mary's womb.
[B]ehold, an angel of the Lord appeared to him in a dream, saying, “Joseph, son of David, do not fear to take Mary your wife, for that which is conceived in her is of the Holy Spirit; she will bear a son, and you shall call his name Jesus, for he will save his people from their sins.” All this took place to fulfill what the Lord had spoken by the prophet: "Behold, a virgin shall conceive and bear a son, and his name shall be called Emman′u-el” (which means, God with us). When Joseph woke from sleep, he did as the angel of the Lord commanded him; he took his wife, but knew her not until she had borne a son; and he called his name Jesus.
St. John Paul II referred to this biblical event in his apostolic letter on St. Joseph, Redemptoris Custos.
In the words of the "annunciation" by night, Joseph not only heard the divine truth concerning his wife's indescribable vocation; he also heard once again the truth about his own vocation. This "just" man, who, in the spirit of the noblest traditions of the Chosen People, loved the Virgin of Nazareth and was bound to her by a husband's love, was once again called by God to this love.
As a result, in the Church we can refer to two different "annunciations," one to the Blessed Virgin Mary and the other to St. Joseph.