Tretha is of Welsh origin and its meaning is "joyful". This name has been used historically but it is quite rare today. It was most popular during the late 19th to early 20th centuries, especially in Wales. Tretha is also associated with the surname Trethewy, which suggests that it may have been a family name at one point. Interestingly, there is a village named Trethewey in Cornwall, England, which could potentially be connected to this name. As for pronunciation, Tretha is typically said as "TRET-uh".
"Tretha saw its peak in popularity with six births in 1932. After a dip, it regained some traction with five births each in 1950 and 1960, totaling sixteen babies named Tretha over these years."