Her large pink face was appropriately solemn, and her plum-coloured satin with pale blue side-panels, and blue ostrich plumes in a small satin bonnet, met with general approval; but before she had settled herself with a stately rustle in the pew opposite Mrs. Archer’s the spectators were craning their necks to see who was coming after her.
Archer had tried to persuade May to spend the summer on a remote island off the coast of Maine (called, appropriately enough, Mount Desert), where a few hardy Bostonians and Philadelphians were camping in "native" cottages, and whence came reports of enchanting scenery and a wild, almost trapper-like existence amid woods and waters.
There are no more uses of "appropriate" identified with this meaning, but check unspecified meaning below.
It was the custom, in old New York, for brides to appear in this costly garment during the first year or two of marriage: his mother, he knew, kept hers in tissue paper in the hope that Janey might some day wear it, though poor Janey was reaching the age when pearl grey poplin and no bridesmaids would be thought more "appropriate."
There are no more uses of "appropriate" in the book.