Coagulated Milk (Yogurt)
"Pour the coagulated milk on a fine sieve and let the whey run off. Then lay in a soup plate. Serve with crushed sugar and cream; or hang in a muslin bag, and allow it to drip, and become hard. Serve with cream and sugar. Pot cheese is made by heating coagulated milk, draining off the whey in a bag, and then mixing with the curd, salt, and sometimes a little sage or some other herb, as a flavoring, and then making it into little balls or cakes. In order that such cheese should be palatable, the coagulated milk must not be bitter in taste."
From The Philosophy of Housekeeping 1859
Finding a reference for yogurt was rather difficult until I stumbled across Thirty-five Years in the East, 1852. On pages 396-397 there is a table of words with translations in Latin, English, French, German, Turkish, Arabian, Persian and Cashmere. Yogurt is listed as Turkish and translated into English as coagulated milk. The French translation is lait caille.
The first real mention of the word yogurt, that I could find, wasn't until Mr. Kellogg promoted it in his Battle Creek Idea, 1910.