Pieces of bread over which a soup or broth is poured. Known at least since the 'Ayenbite of inwyt' of about 1340 "Ase is a zop of hot bryead huanne me hit poteþ in-to wyn." and in a 15Cent cookery book we find "Then cast the same licour vppon þe Soppes, and serue hit forthe fore a good potage". Broth-on-Sops as a method of service appears repeatedly until, by the early 19Cent it was necessary for writers to explain what this old-fashioned practice was.
Although this manner of service, once commonplace, is now rare or extinct in England, where it has evolved into things-on-toast, a variant continues to be offered in parts of Canada as 'hot sandwich with gravy' The name is carried on in Mexico and the Southern USA where 'sopes mexicanos' are thick corn bread-cake made from masa harina, water, salt, and oil with toppings, like chicken, vegetables, and salsa.
Canadian hot chicken sandwich
Image: https://www.rosacooking.com
Sopes Mexicanos
Image: patijinich.com
Some receipts including sops include:
Aleberry
Chickens with Lettuce
Milk Soup
Oil Soup
Tripe with Spinach
Poultry with Citrus Sauce
Marrow Toast
Red Herring
Many more references will be found in old cookbooks such as:
The Accomplisht Cook, 1660
The Forme of Cury, 1390
The Closet of Sir Kenelm Digby, 1669
The Compleat Cook, 1658