[one-night stand] {n. phr.} 1. A single performance given by a […]

[open letter] {n. phr.} A public message in the form of […]

[open market] {n. phr.} Goods or securities available for purchase by […]

[open marriage] {n. phr.} An arrangement by mutual agreement between husband […]

[open question] {n. phr.} A debatable issue. * /Whether assisted suicide […]

[open sesame] {n. phr.}, {literary} Immediate means of entrance, or unobstructed […]

[open shop] {n. phr.} A factory or firm that employs both […]

[open-door policy] {n. phr.} A policy that states that newcomers are […]

[opposite number] {n. phr.} A person occupying the same position as […]

[opposite sex] {n. phr.} The sex different from the one being […]