Smocks are a loose, lightweight overgarment worn to protect the clothing while working.
The use of needlework to control fullness is a very old technique. Smocking needle work continues today and is a popular addition to fancy collars as well as garments for younger children. Early 19th Century work Garment European farm workers wore smock frocks in the 18th and 19th Century. This was a common atire for farmers and working men. Americans of English decent may well have worn the smock.