informalball-gamesbaseballgamesHaving reached a base as a runner and being positioned there, awaiting further action from a subsequent batter.

• With one out and no men on, Tristen Carranza belted a ball to the opposite field for a solo home run to put the NM State deficit at just 2-1.
• Although Stanford was outhit 15-6, the Cardinal stranded eight runners to UCLA's three, hitting just 3-15 with runners on compared to the Bruin's 9-22.

ball-gamescricketgamesWithin the half of the field on the same side as the batsman's legs; the left side for a right-handed batsman.

• The captain moved two fielders to the on side.
• Ponsonby-Smythe hit a thumping on drive.

ball-gamesgameshobbiesOf a ball, being the next in sequence to be potted, according to the rules of the game.

• If the player fails to hit the ball on, it's a foul.

actingbroadcastingdramaActing in character.

informalPerformative or funny in a wearying manner.

• He always has to be on, it's so exhausting.

Menstruating.

• It still gets in the way of her doing things like swimming, and she avoids sleepovers when she's "on".

Expressing figurative placement, burden, or attachment.

• All of the responsibility is on him.
• I put a bet on the winning horse.

Denoting physical contact or interaction with an object, such as impact or application of force.

• tug on the rope; push hard on the door

Denoting physical contact or interaction with an object, such as impact or application of force.

• I stubbed my toe on an old tree stump.
• I caught my fingernail on the door handle.

Denoting physical contact or interaction with an object, such as impact or application of force.

• to play on a violin or piano

Supported by (the specified part of itself).

• A table can't stand on two legs.
• After resting on his elbows, he stood on his toes, then walked on his heels.

At (a certain value or level).

• The Tories are on twenty-five percent in this constituency.
• The blue team are on six points and the red team on five.

At (a certain position within a sequence).

• I'm on question four.

At or during the date or day of.

• Born on the 4th of July.
• On Sunday I'm busy. I'll see you on Monday.

At (a given time after the start of something).

• Smith scored again on twelve minutes, doubling Mudchester Rovers' lead.
• The Spain striker had given Chelsea the lead on 29 minutes but was shown a straight red card 10 minutes later for a rash challenge on Mark Gower.

At (an instant or cusp).

• on the stroke of midnight; on the "B" of "Bang!"
• on the point of leaving; on the verge of giving up

Dealing with the subject of; about; concerning.

• I was reading a book on history.
• The city hosted the World Summit on the Information Society

Indicating a means or medium.

• I saw it on television.
• Can't you see I'm on the phone?

Indicating the target of, or thing affected by, an event or action.

• They planned an attack on London.
• The soldiers mutinied and turned their guns on their officers.

informalIn the possession of.

• I haven't got any money on me.

Because of; upon the basis of (something not yet confirmed as true).

• to arrest someone on suspicion of bribery
• to contact someone on a hunch

At the time of (and often because of).

• On Jack's entry, William got up to leave.
• On the addition of ammonia, a chemical reaction begins.

Arrived or coming into the presence of.

• I need to get my planting done, as the season will soon be on us.
• Before we knew it, the forest was on us, and the air grew colder and damper.

Paid for by.

• The drinks are on me tonight, boys.
• The meal is on the house.

Toward; for; indicating the object of an emotion.

• Have pity or compassion on him.

Indicating the person experiencing an emotion, cold, thirst, hunger, etc.

• I had a terrible thirst on me.
• '[…] the hunger is on me to carry my sword in distant places.' Mynyddog bowed his head.

Indicating a means of subsistence or sustenance.

• They lived on ten dollars a week.
• The dog survived three weeks on rainwater.

Engaged in or occupied with (an action or activity).

• He's on his lunch break.
• I'm on nights all this week.

Regularly taking (a drug).

• You've been on these antidepressants far too long.

Under the influence of (a drug, or something that is causing drug-like effects).

• He's acting crazy because he's on crack right now.

In addition to; besides; indicating multiplication or succession in a series.

• heaps on heaps of food
• mischief on mischief; loss on loss

Indicating dependence or reliance.

• I depended on them for assistance.
• He will promise on certain conditions.

Serving as a member of.

• He is on the jury; I am on the committee.

By virtue of; with the pledge of.

• He affirmed or promised on his word, or on his honour.

To the account or detriment of; denoting imprecation or invocation, or coming to, falling, or resting upon.

• On us be all the blame.
• A curse on him!

Against; in opposition to.

• The fight was three on one, and he never stood a chance.

human-scienceslogicmathematicsAccording to, from the standpoint of; (expressing what must follow, whether accepted or not, if a given premise or system is assumed true).

• On naturalism, it is therefore difficult to find a ground for ultimate moral hope.

ball-gamesgameshobbiesIn a position of being able to pot (a given ball).

• All the way around the table, off four cushions, and ... and he's on the black!

mathematicssciencesHaving as identical domain and codomain.

• a function on #92;mathbb#123;R#125;

mathematicssciencesHaving Vⁿ as domain and V as codomain, for the specified set V and some integer n.

• an operator on #92;mathbb#123;Z#125;

mathematicssciencesGenerated by.

• the free group on four letters

mathematicssciencesDivided by.

• Twenty on three.

obsoletedialectalregionalOf.

• I never seen 'im, and that's the truth on it.
• Be not jealous on me.

obsoleteAt the peril of, or for the safety of.

• Hence on thy life: the captive maid is mine; / Whom not for price or pray'rs I will reſign: [...]