# Confusion about terminology. What is a principal?

**URL:** <https://forum.dfinity.org/t/confusion-about-terminology-what-is-a-principal/7741>\
**Category:** Getting Started\
**Created:** [October 7, 2021, 4:05am UTC](https://forum.dfinity.org/t/confusion-about-terminology-what-is-a-principal/7741 "2021-10-07T04:05:43Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![tommccann](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/tommccann/32/19421_2.png) [@tommccann](https://forum.dfinity.org/u/tommccann)\
**Post date:** [October 7, 2021, 4:05am UTC](https://forum.dfinity.org/t/confusion-about-terminology-what-is-a-principal/7741/1 "2021-10-07T04:05:43Z")

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In this page of the documentation https://sdk.dfinity.org/docs/developers-guide/sdk-guide.html it states the following:

> Regardless of the development workflow you choose, keep in mind that when you deploy a canister for the first time, either on a local execution environment or on the Internet Computer, a unique [principal identifier](https://sdk.dfinity.org/docs/developers-guide/glossary.html#g-principal) is created for your canister smart contract.

From reading the glossary I was led to believe that a principal describes a person with an identity, yet the above paragraph implies that the canister has a principal id. Does it mean that a principal identifier can be associated with a canister? i.e. that a principal identifier can be the controller for a canister?

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**Author:** ![wole](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/wole/32/2650_2.png) [@wole](https://forum.dfinity.org/u/wole)\
**Post date:** [October 7, 2021, 11:22am UTC](https://forum.dfinity.org/t/confusion-about-terminology-what-is-a-principal/7741/2 "2021-10-07T11:22:17Z")

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Useful discussion here [What is the difference between Account identifier, Principal identifier and Public-Key](https://forum.dfinity.org/t/what-is-the-difference-between-account-identifier-principal-identifier-and-public-key/3677)

Yes, a principalId (i.e. a user) can be the controller. A controller is an identity that has rights to manage the canister. It is usually the _textual representation_ of a principal.

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**Author:** ![senior.joinu](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/senior.joinu/32/9240_2.png) [@senior.joinu](https://forum.dfinity.org/u/senior.joinu)\
**Post date:** [October 7, 2021, 11:55am UTC](https://forum.dfinity.org/t/confusion-about-terminology-what-is-a-principal/7741/3 "2021-10-07T11:55:59Z")

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Principal describes an _entity_ (like a legal entity) - an actor in a system which is enabled to perform actions on their own.

I don’t know for sure, but there is an opinion that this term was inspired by [Agency agreement](https://en.wikipedia.org/wiki/Agency_agreement) terminology. Which seems okay to me, since it is pretty simple to describe a canister like an agent of the agency agreement.

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**Author:** ![cyaolong](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/cyaolong/32/2303_2.png) [@cyaolong](https://forum.dfinity.org/u/cyaolong)\
**Post date:** [October 7, 2021, 1:21pm UTC](https://forum.dfinity.org/t/confusion-about-terminology-what-is-a-principal/7741/4 "2021-10-07T13:21:34Z")

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As Principal ID to me, it can be referred to a normal user enjoying IC Dapps, and it can also be an ID for a Canister where Dapps run on it.