Ding ding ding! We have a winner. After reaching out to the customer, you are correct, MintJulep.
T/S stands for taper per side. Hopefully if anybody else has this question, this thread can help them out. Thanks for the responses, everybody.
I received a drawing from a customer with an abbreviation that I can't seem to put my finger on...
I think I understand what it's trying to convey, which is a .275 dia hole, then tangent edges upward and outward at a 2° angle. But what does "T/S" mean?