O.S.

O.S. (countable and uncountable, plural O.S.'s)

1. (countable, computing) Initialism of operating system.
2. (calendar systems) Abbreviation of Old Style.
3. (eyewear) Initialism of O.S. (“oculus sinister”).; (the left eye from the patient's point of view) (in eyeglass and contact lens prescriptions)

• (eyewear): O.D.

• S&O, SO, So, So., s.o., s/o, so

O.S.

1. (Can we verify⁽⁺⁾ this sense?) (eyewear) O.S. (“oculus sinister”) (the left eye from the patient's point of view)

• O.D.