Nose pads
Small adjustable pads on metal arms that rest a frame on the sides of the nose.
Also: pad arms
Many metal and rimless frames sit on two soft pads mounted on small wire arms, which an optician can bend to raise or lower the frame and fit it to the nose bridge. Plastic frames usually have pads moulded into the frame, which cannot be adjusted, so their bridge must fit from the start. Silicone pads are common now; older pads were glass or hard plastic.