The Morning Suit
In the early 1880s, a compromise was made between the, by then, rigid formality of the Frock Suit and the laid back informality of the Sack Suit. The result was the Morning Suit.
This suit retained the gray, striped trousers and black vest and coat of the Frock Suit, but softened the lines a bit by rounding the bottom hem of the coat and shrinking the lapels.
Further, unlike the frock suit for which a top hat was essential (at least in town), the Morning Suit allowed a certain amount of latitude in headgear, with top hats for business and formal calls, and a tall crowned bowler for less dressy occasions. There was also more latitude with neck wear than with a Frock Suit, with Windsor ties more common than bow ties.
The Morning Suit could be worn at weddings, funerals, calls of ceremony, teas and other daytime formal occasions. It could also be worn for business, but the Frock Coat still reigned supreme with the management in the office. The Sack Suit or Morning Suit was suitable for more junior staff and clerks.