English: A bishop’s coat of arms is used on documents, letterheads and other official items as a symbol of his office.

At the top of Bishop Martin’s coat of arms is a green galero, a broad-brimmed hat once worn by clergy that now designates their rank. On either side are six green tassels called “houppes” which also signify the rank of a bishop in the Church.

To the viewer’s right is the Franciscan coat of arms. Featuring the traditional Franciscan Tau cross with two arms crossing one another, it is rich in symbolism. The two arms, one Christ’s and the other St. Francis of Assisi’s, both bear the stigmata. They symbolize God’s love and Francis’s loving response to the Word made incarnate, Taberski explained. It is an image found throughout the ministries, friaries, missions and sites served by the Franciscan order.

On the right side of the shield, the top (known as the “chief”) and the bottom (the “base”) feature references to George Calvert and his son Cecil Calvert – the first and second barons of Baltimore. The Calverts were among the first Catholics to arrive in colonial America. They established the then Province of Maryland as a safe place for English Catholics to emigrate to since they were no longer able to freely practice their faith at home. In the coat of arms, the use of six vertical stripes – alternately gold and black, with the diagonal stripe in color – recalls Bishop Martin’s hometown of Baltimore.

To the viewer’s left are two symbols of the Diocese of Charlotte. On the top is a Celtic cross symbolizing St. Patrick, patron of the diocesan cathedral. Below it, a crown symbolizes Queen Charlotte, consort of King George III of England, for whom the city of Charlotte was named.

The coat of arms also includes Bishop Martin’s personal motto, “Duc in altum,” which means “put out into the deep,” and are the words Jesus spoke to Peter in the Gospel of Luke (5:4).

Behind the shield is a gold San Damiano cross as the processional cross, a symbol of the bishop’s office. This particular style of cross is significant to Franciscans because the order’s movement began when St. Francis heard Jesus tell him from the cross in the chapel of San Damiano in Italy: “Francis, go rebuild my Church for it is falling to ruins.” At first, St. Francis thought it was a literal command to rebuild the chapel. Soon after, he realized it was a call to a greater mission: creating an order that would transform the life of the Church worldwide.

Reference: https://catholicnewsherald.com/259-news/bishop-martin/10492-bishop-martin-s-coat-of-arms-harkens-to-his-background