Joss is used predominantly in the English language, and its origin is Old French, Hebrew, and Breton. Joss is a diminutive form of the name Jocelyn (English). Joss is also a variant (English) of the name Joseph (English, French, and German).Joss is also a variant of the name Joshua (English). Joss is also a variant of the name Joyce (English). Joss is not regularly used as a baby name for boys.It is not listed in the top 1000 names. In 2012, out of the group of boy names directly linked to Joss, Joshua was the most commonly used.oss is also a variant of the name Joyce (English). Joss is not regularly used as a baby name for boys. It is not listed in the top 1000 names. In 2012, out of the group of boy names directly linked to Joss, Joshua was the most commonly used.