Since vs. Upon

Attribute	Since	Upon
Definition	From a specific point in time until now	At the time of
Usage	Used to indicate a starting point in time	Used to indicate a specific time or event
Examples	Since yesterday, Since 2010	Upon arrival, Upon completion

Definition

Since and upon are both prepositions that are used to indicate a point in time or a starting point for an action. Since is typically used to refer to a specific point in time when something began, while upon is used to indicate a more general starting point or condition.

Usage

Since is commonly used to refer to a specific time in the past when an action started or an event occurred. For example, "I have been working here since 2010." Upon, on the other hand, is often used to indicate a more general starting point or condition. For example, "Upon arriving at the airport, we realized our flight was delayed."

Duration

Since is often used to indicate the duration of an action or event that started in the past and continues to the present. For example, "I have been studying French since high school." Upon, however, is not typically used to indicate duration but rather a specific starting point or condition. For example, "Upon hearing the news, she burst into tears."

Formality

Since is considered more informal than upon. Since is commonly used in everyday speech and writing, while upon is often used in more formal contexts such as academic writing or legal documents. For example, "Since you're here, let's get started" is more casual than "Upon further investigation, it was determined that the suspect was innocent."

Connection

Since is often used to indicate a cause-and-effect relationship between two events or actions. For example, "Since it was raining, we decided to stay indoors." Upon, on the other hand, is used to indicate a more immediate connection between two events or actions. For example, "Upon hearing the news, she immediately called her family."

Transition

Since can also be used to indicate a transition from one point in time to another. For example, "Since then, I have not heard from him." Upon, however, is not typically used in this way and is more commonly used to indicate a specific starting point or condition. For example, "Upon arrival, please proceed to the check-in desk."

Conclusion

In conclusion, since and upon are both prepositions that are used to indicate a point in time or a starting point for an action. While since is typically used to refer to a specific time in the past when something began and is more informal in nature, upon is used to indicate a more general starting point or condition and is considered more formal. Both words have their own unique uses and nuances, and understanding the differences between them can help improve your writing and communication skills.