AR: Anti-Reflective. A coating that reduces reflection on the lenses.
BAL: the Rx calls for balance lenses, meaning the same Rx for each eye.
CYL: the Cylinder. Combined with the AXIS, the CYL corrects an astigmatism.
DV: distance vision.
FT: flat-top bifocal.
NV: near vision.
NV-ADD (also ADD): the Near Vision (NV) Reading ADDition
OD: Latin for Oculus Dexter, meaning the right eye.
OS: Latin for Oculus Sinister, meaning the left eye.
OU: Latin for Oculus Uterque, meaning each eye.
PD (Pupillary Distance): the PD is the measurement of the distance between your pupils. This is needed for the manufacturer of the eyeglasses to know where to place the optical center on each lens, so you can see well with the glasses.
PL: Plano. Latin for "flat." If this is in the SPH section of an Rx, it means no nearsighted or farsighted correction is needed.
RX: a prescription.
SPH: the first section on an Rx. It corrects nearsighted or farsighted vision.
UV: the abbreviation of ultraviolet. UV light is invisible to the human eye, but it is UV light that gives us a sunburn, and too much exposure to it can damage the eye.
VA: Visual acuity: how well the eye can see. Sometimes this may be written on an Rx, with a number such as 20/20. This would indicate that with eyeglasses made to this Rx, the vision would be corrected to 20/20 vision.