| Once bitten, twice ___ | 22 |
| Once bitten, so to speak | 24 |
| Once around, to an astronaut | 28 |
| Once around, for John Glenn | 27 |
| Once around the park, say | 25 |
| Once around the moon, e.g. | 26 |
| Once around the course | 22 |
| Once around the Brickyard | 25 |
| Once around a racetrack | 23 |
| Once and quince, for example | 28 |
| Once across the Rio Grande? | 27 |
| Once - lifetime connector | 25 |
| Onboard GPS suggestion | 22 |
| Onassis, to his friends | 23 |
| Onassis's nickname | 22 |
| Onassis who married Jackie | 26 |
| Onager treading insect? | 23 |
| On-___ (bit of gossip) | 22 |
| On-the-way-out PC component | 27 |
| On-the-town time for many | 25 |
| On-the-spot TV programs | 23 |
| On-the-spot canvass of voters | 29 |
| On-the-playing-field animal | 27 |
| On-the-job training slogan | 26 |
| On-the-job protection org. | 26 |
| On-the-hour radio offering | 26 |
| On-the-green golf strokes | 25 |
| On-the-go morning snack | 23 |
| On-site shucking sites | 22 |
| On-site day care, perhaps | 25 |
| On-screen trash can, for one | 28 |
| On-screen trash can, e.g. | 25 |
| On-screen surgery resident | 26 |
| On-screen nephrologist | 22 |
| On-ramp posting, perhaps | 24 |
| On-location broadcasts | 22 |
| On-line ticket service | 22 |
| On-line sect. for newbies | 25 |
| On-line publications, briefly | 29 |
| On-line publication, briefly | 28 |
| On-line periodical, for short | 29 |
| On-line option for investors | 28 |
| On-line investing company | 25 |
| On-line image producer | 22 |
| On-line forum precursor | 23 |
| On-line financial corp. | 23 |
| On-line exchanges, briefly | 26 |
| On-line correspondence | 22 |
| On-line community manager | 25 |
| On-line columnist Drudge | 24 |
| On-line classifieds site | 24 |
| On-line brokerage firm | 22 |
| On-demand video website | 23 |
| On-demand spa service? | 22 |
| On-call doctors' devices | 28 |
| On-base percentage, e.g. | 24 |
| On-base percentage and others | 29 |
| On-air performers, in the biz | 29 |
| On, in French place names | 25 |
| On, as a kerosene lamp | 22 |
| On _____ with (equal to) | 24 |
| On _____ of (representing) | 26 |
| On _____ boat to China | 22 |
| On _____ (when wanted) | 22 |
| On _____ (theoretically) | 24 |
| On _____ (counting calories) | 28 |
| On ____ with: equal to | 22 |
| On ____ with (equal to) | 23 |
| On ____ (from the barrel) | 25 |
| On ___ with (equivalent to) | 27 |
| On ___ with (equal to) | 22 |
| On ___ with (comparable) | 24 |
| On ___ with (amicable) | 22 |
| On ___ the world (elated) | 25 |
| On ___ streak (winning) | 23 |
| On ___ of (as a proxy for) | 26 |
| On ___ (wrestling term) | 23 |
| On ___ (without commitment) | 27 |
| On ___ (without a contract) | 27 |
| On ___ (without a buyer) | 24 |
| On ___ (when challenged) | 24 |
| On ___ (Wall St. risk) | 22 |
| On ___ (trying to succeed) | 26 |
| On ___ (trying to lose) | 23 |
| On ___ (taking a challenge) | 27 |
| On ___ (ready for golf) | 23 |
| On ___ (pending approval) | 25 |
| On ___ (out with someone) | 25 |
| On ___ (out of the nest) | 24 |
| On ___ (like some jobs) | 23 |
| On ___ (in little space) | 24 |
| On ___ (having success) | 23 |
| On ___ (having good luck) | 25 |
| On ___ (gossip's morsel) | 28 |
| On ___ (counting calories) | 26 |
| On ___ (continually winning) | 28 |
| On ___ (available for duty) | 27 |
| On ___ (at loggerheads) | 23 |
| On ___ (as challenged) | 22 |
| On __: sandwich specification | 29 |