Something that is not compulsory, especially part of an academic course.

(physics) a property caused by asymmetrical molecular or crystal structure that enables a compound or crystal to rotate the plane of incident polarized light

(chemistry) Any one of a number of compounds that exhibit optical isomerism.

(chemistry, of a crystal or compound) Exhibiting optical activity.

(computing) The electronic identification and digital encoding of printed or handwritten characters by means of an optical scanner and specialized software.

(finance) A put option that makes a payoff in the event the issuer of a specified reference asset defaults.

(nautical) A small centre-board sailing dinghy designed to train and introduce young children into sailing.

(naturism) Allowing and encouraging nudity but tolerating the wearing of clothes, as between nudist and clothing compulsive. Abbreviation: C.O.

Alternative spelling of fibre optic

Alternative spelling of fibre optic