Short form of Teresa, possibly from Greek 'therizein' meaning to harvest.
Tess is most often a short form of Theresa or Teresa, though it has long stood comfortably on its own. The deeper etymology of Theresa is debated, but it is usually linked to Greek, possibly through Therasia, the name of an Aegean island, and over the centuries it gathered meanings ranging from "summer" to "harvest" to a more mysterious sense of classical place-name antiquity. Tess emerged as the brisk, bright diminutive: one syllable, clear as a bell, with a softness at the end that keeps it from sounding severe.
Like many nicknames that matured into independent given names, it feels intimate without being flimsy. Its literary halo comes most powerfully from Thomas Hardy's Tess of the d'Urbervilles, published in 1891. Hardy's heroine made the name unforgettable, and ever since, Tess has carried an undertone of poignancy, dignity, and rural English beauty.
At the same time, the name has been borne by actresses, writers, and fictional heroines who helped it move beyond Victorian tragedy into modern confidence. In usage, Tess has evolved from affectionate shorthand to a name prized for being trim, classic, and quietly strong. It avoids fussiness, which is part of its enduring appeal. Cultural associations range from Saint Teresa by ancestry to Hardy by mood, giving Tess an unusual blend of sacred lineage, literary gravity, and contemporary simplicity.