Terras or Tarras, spelling changes depending on registrar. Local dialect affects spelling as most people were illitterate & couldn,t read or write! I found a Terrasse in Tayport! My research through the male side took me to Elgin/Forres c.1575 AD.
Name appears to come from a tract of land outside Forres called "The Tarras" There exists a farm called Littleton of Tarrus. The 1911 census has my family listed as Terrus, obviously an incompleted A! This is of little use to our Scandanavian relations in Norway & Sweden, but may explain the varaiation of spelling.