O

[once bitten, twice shy]

See: [BURNT CHILD DREADS THE FIRE].

[once for all]

See: [ONCE AND FOR ALL].

[once in a blue moon]  {adv. phr.}

Very rarely; very seldom; almost never.

Coin collecting is interesting, but you find a valuable coin only once in a blue moon.

* /Once in a blue moon someone grows a very pale marigold, but no truly white  […]

[once in a while]  {adv. phr.}

Not often; not regularly; sometimes; occasionally.

We go for a picnic in the park once in a while.

Once in a while the puppy would run away, but usually he stayed in the yard.

Syn.: [AT TIMES], [FROM TIME TO  […]

[once-over]  {n.},  {slang}

1. A quick look; a swift examination of someone or something. — Usually used with "give" or "get".

The new boy got the once-over from the rest of the class when he came in.

* /Bob gave his paper the once-over before  […]

[once upon a time]  {adv. phr.}

Sometime before now, long ago.

Once upon a time she was thought to be the most talented actress in the country.

- Often used at the beginning of fairy stories.

* /Once upon a time there lived a king who had an ugly  […]

[on cloud nine]  {adj. phr.},  {slang}

Too happy to think of anything else; very happy.

Ada has been on cloud nine since the magazine printed the story she wrote.

We were on cloud nine when our team won the state championship.

Compare: [ON TOP  […]

[on condition that]  {conj.}

Providing that; if.

I will lend you the money on condition that you pay it back in one month.

[on deck]  {adv.} or  {adj. phr.}

1. On a floor of a ship open to the outdoors.

The passengers were playing shufflehoard on deck.

The sailors kept busy cleaning and painting on deck.

2.  {informal}

Ready to do something; present.

* /The scout  […]

[on deposit]  {adv. phr.}

In a bank.

I have almost $500 on deposit in my account.