[of the first water]{adj. phr.}, {informal} Of the finest quality; superior; very good; best. •/The jeweler chose diamonds of the first water for the queen’s crown./ •/The dance program at graduation was of the first water./ Compare: FIRST-CLASS.

[of the same mind]{adv. phr.} In agreement; in consonance. •/It is a good thing when father and son are of the same mind regarding business and politics./

[oil] See: POUR OIL ON TROUBLED WATERS.

[oil the wheels] See: GREASE THE WHEELS.

[ointment] See: PLY IN THE OINTMENT.

[old] See: CHIP OFF THE OLD BLOCK, COMFORTABLE AS AN OLD SHOE, COMMON AS AN OLD SHOE, OF OLD.

[old as the hills]{adj. phr.} Very old; ancient. •/"Why didn’t you laugh?" she asked. "Because that joke is as old as the hills," he answered./

[old boy network]{n. phr.} A system whereby men who went to the same school help each other to get good jobs, regardless of their ability or training. •/Peter got his lucrative job thanks to the old boy network rather than because of his qualifications./ Compare: OLD COLLEGE TRY.

[old boy] or [old chap] {n.}, {Chiefly British} One of the men educated at the same institution and bound by strong ties of loyalty to each other. •/He got the job because the boss was another old boy./

[old college try]{n. phr.} An attempt to win a favor from another by mentioning the fact that one had gone to the same college or university as the party from whom the favor is requested. •/Since he needed a job, he decided to use the old college try when he contacted Jerry, but it didn’t work./ Compare: OLD BOY NETWORK.

[old country]{n. phr.} Primarily Europe, but also any country other than the United States where one originally came from. •/Al’s wife was born in Chicago but Al himself is from the old country, Ireland./

[old flame]{n. phr.} An erstwhile lover. •/Did you know that Meg was one of Howard’s old flames?/

[old guard]{n. phr.} People whose ideas may be out of date, but who have been in power for a long time. •/There will not be any change in policy at the company, as long as the old guard still works here./

[old hand]{n. phr.} An experienced and highly skilled expert at some particular job. •/Uncle Joe is an old hand at repairing car engines./

[old hat]{adj.}, {informal} Old-fashioned; not new or different. •/By now, putting satellites in orbit is old hat to space scientists./ •/Andrea thought her mother’s ideas about dating were old hat./

[old maid]{n. phr.} A spinster; a woman who has never married. •/Because my old maid aunt is a terrific cook as well as a good-looking woman, nobody understands why she never married./

[old money] Contrast: NEW MONEY.

[Old Nick] See: FULL OF THE OLD NICK.

[old school tie] See: OLD BOY NETWORK, OLD COLLEGE TRY.

[old story]{n.} An everyday occurrence; something that often happens. •/Jane’s temper tantrums were an old story./ •/It’s an old story when a woman divorces her husband for too much drinking./

[old-timer]{n.} An old person who remembers bygone days, matters, and personalities. •/There was an old-timer at the party who told us interesting details about World War II./ Contrast: OLD GUARD, OLD HAND.

[old world]{n. phr.} Europe, the continent; a continental manner. •/Tom had an old world manner that thoroughly charmed all the ladies./ Compare: OLD COUNTRY.

[olive branch]{n. phr.} An overture; a symbol of peace. •/Tired of the constant fighting, the majority government extended an olive branch to the militant minority./

[on account]{adv. phr.} As part payment of a debt; to lessen the amount owed. •/John paid $10 down and $5 on account each month for his bicycle./

[on account of]{prep.} As a result of; because of. •/The picnic was held in the gym on account of the rain./ Compare: ON ONE’S ACCOUNT, OF ONE’S OWN ACCORD.

[on a dime]{adv. phr.}, {informal} In a very small space. •/Bob can turn that car on a dime./ •/Tom says his new sports car will stop on a dime./

[on-again, off-again] See: OFF-AGAIN, ON-AGAIN.

[on air] See: WALK ON AIR.

[on a limb] See: OUT ON A LIMB.

[on all four] See: HIT ON ALL FOUR.

[on all fours]{adv. phr.} 1. On all four legs; on hands and knees. •/Fido sat up to "beg" but dropped down on all fours to eat the dog biscuit Sam gave him./ •/Billy’s father got down on all fours and gave the baby a ride./ 2. {informal} On a level of equality; of the same value. •/Wigs may be widely used, but they are still not on all fours with beautiful natural hair./

[on an average] or [on the average] {adv. phr.} In most cases; usually. •/On an average Dan’s mother has to ask him three times before he helps with the dishes./ •/On the average, Mr. Blank trades in his car for a new one every three years./

[on and off] See: OFF AND ON.

[on an even keel]{adv. phr.}, {informal} In a well-ordered way or condition; orderly. •/When the football rally seemed almost ready to become a riot, the principal stepped to the platform and got things back on an even keel./

[on a pedestal]{adv. phr.} Lovingly honored and cared for. •/Mrs. Raymond’s children served her breakfast in bed on Mother’s Day and later took her out to dinner. She felt on a pedestal./ •/Bill is always waiting on his fiancee and bringing her flowers and candy. He has certainly put her on a pedestal./

[on approval]{adv. phr.} With the understanding that the thing may be refused. •/Mr. Grey bought his camera on approval./ •/The company offered to send a package of stamps on approval./

[on a scratched horse] See: PUT ONE’S MONEY ON A SCRATCHED HORSE.

[on a shoestring]{adv. phr.} With little money to spend; on a very low budget. •/The couple was seeing Europe on a shoestring./

[on a volcano] See: SIT ON A VOLCANO.

[on behalf of] See: IN BEHALF OP.

[on board(1)]{prep.} On (a ship). •/Joan was not on board the ship when it sailed./

[on board(2)]{adv.} or {adj. phr.} On a ship. •/The captain was not on board when the S.S. Flandre sailed./ •/A ship was leaving the harbor, and we saw the people on board waving./

[on borrowed time] See: LIVE ON BORROWED TIME.

[on call]{adj. phr.} 1. Having to be paid on demand. •/Jim didn’t have the money ready even though he knew the bill was on call./ 2. Ready and available. •/This is Dr. Kent’s day to be on call at the hospital./ •/The nurse is on call for emergency cases./

[once] See: AT ONCE, EVERY NOW AND THEN or EVERY ONCE IN A WHILE.

[once and for all]{adv. phr.} 1. One time and never again; without any doubt; surely; certainly; definitely. •/Let me say, for once and for all, you may not go to the party Saturday./ •/For once and for all, I will not go swimming with you./ 2. Permanently. •/Bill and Tom asked the teacher to settle the argument once and for all./ •/The general decided that two bombs would destroy the enemy and end the war once and for all./

[once bitten, twice shy] See: BURNT CHILD DREADS THE FIRE.

[once for all] See: ONCE AND FOR ALL.