This title is peculiar to fly-kinden. In the Days of Lore, flies were mostly slaves and servants, with no real cities of their own. The Spider aristoi frequently had many hundreds of servants in a household, with some made more important and put over others. The position of head servants at some point became hereditary, and the families involved were identified with the use of the prefix 'te'.
When flies eventually founded their own settlements, the head servants continued to lead and were considered some sort of nobility. Families with the te are still accorded some degree of respect by flies across the Lowlands.
In the city of Solarno live the descendants of Spiders who fled there as a sort of self-imposed exile from defeat in the Dance in the Spiderlands. With them they brought servants, but only the most important ones, since they were frequently pursued by enemies or much reduced in resources. Consequently many, if not most, of the flies in Solarno are descended from the 'noble' lines, meaning the title is much less important.