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

[optional origin] {n.} Stipulation in international commodities contract whereby the seller […]

[other fish to fry] {n. phr.}, {informal} Other things to do; […]

[out-of-pocket expenses] {n. phr.} Expenses one has to pay for oneself, […]

[outback] {n.} 1. The remote and uncultivated wilderness areas of Australia […]

[outer space] {n.} What is outside of the earth's air. * […]

[overhead] {n.} Expenses incurred in the upkeep of one's plant and […]

[pack of lies] {n. phr.} An unbelievable story; unprovable allegations. * […]

[pack rat] {n.}, {informal} A person who cannot part with old, […]

[paddy wagon] {n.}, {informal} A police van used for transporting prisoners […]