In German, name Joss means – Diminutive of Jocelyn: One of the Goths. Introduced into Britam as a masculine name during the Norman Conquest, Jocelyn was adopted as a feminine first name in the early 20th century.. Other origins for name Joss include – German, Israeli, Hebrew. Name Joss is a unisex name and can be used for a boy or girl name (male or female).