The preposition 'on' has many uses in English. This page summarizes the uses of 'on' as a preposition and provides examples for each type of use. Important prepositional phrases with 'on' are used to introduce and connect ideas are also listed with appropriate examples.
On as a Preposition
On - Time
I will see you on Thursday.
Peter usually walks to work on Fridays.
On - Places
'On' is used flat surfaces both big and small.
We played football on the field.
The book is on the table over there.
'On' is used with planets. The most common usage is 'on earth', but other planets take 'on' as well.
You will find a wide variety of life on earth.
So far, life has not been discovered on Saturn.
On - Onto
Sometimes 'on' is confused with 'onto'. The preposition 'on' indicates that something is already in the position. 'Onto' indicates a movement from one place onto to surface of some type.
The book is on the table. BUT Pete took the book out of his backpack and put it onto the table.
Could you move those clothes onto the sofa?
'On foot' is an exception to stating how something moves with 'by'. For example, I went there by boat, by plane or by car. BUT I went there on foot.
She left her home and went to town on foot.
Jennifer prefers to go shopping on foot.
Important Phrases with On
'On' is used in a number of fixed expressions. These are some of the most common.
'On balance' is used to summarize a situation.
On balance, we need to look for new business soon.
We decided that, on balance, it didn't make sense to invest in new product development.
On condition (that)
'On condition' is used to establish something that must be done in order for something else to happen. 'On condition' can be used in place of 'if'.
We'll send our daughter to Europe this summer on condition that she gets good grades this semester.
On condition that you finish this assignment, I will let you stay out late on Saturday.
On one's own
'On one's own' refers to action that is done by yourself.
Time doesn't like to spend much time on his own. He'd rather be with people.
Mary was proud of having paid for her studies on her own.
On the contrary
'On the contrary' is used to link ideas showing an opposing point of view.
On the contrary, I believe that it will be impossible to succeed in this market.
You might think Wilma is a great employee. On the contrary, she isn't very effective.
On the other hand
'On the other hand' is used when showing both the positive and the negative aspects of a situation.
We'd think there is a lot of potential to the idea. On the other hand, it's certainly a risky proposition.
On the other hand, if you don't spend more time on your homework your grades will get worse.
On the way
'On the way' indicates that something is physically located on the path to somewhere else. 'On the way' can also be used in a figurative sense to indicate that something happened during the course of another action.
Let's meet at the school on the way to the park.
He happened to meet a lot of great people on the way to his success.
On the whole
'On the whole' is used to summarize an opinion or discussion.
On the whole, I think you will agree that our position in the market is excellent.
On the whole, Jack thinks it's a good idea to hire some new employees.
Special Case: On time vs In Time
'On time' means that you have arrived somewhere at the agreed upon time. 'In time' indicates that you have done something within the appropriate amount of time.
I arrived at the meeting on time.
She picked us up at the airport on time.
I finished the report in time for the meeting.
Janice gave her recommendations in time for us to make an informed decision.