Definition of purpose noun from the Oxford Advanced Learner's Dictionary

Oxford3000

purpose

noun
ˈpɜːpəs
 
; ˈpɜːrpəs
 
 
1 [countable] the intention, aim or function of something; the thing that something is supposed to achieveOur campaign's main purpose is to raise money.The purpose of the book is to provide a complete guide to the university.A meeting was called for the purpose of appointing a new treasurer.The experiments serve no useful purpose(= are not useful).The building is used for religious purposes.2 purposes [plural] what is needed in a particular situationThese gifts count as income for tax purposes.For the purposes of this study, the three groups have been combined.3 [countable, uncountable] meaning that is important and valuable to youVolunteer work gives her life (a sense of) purpose.4 [uncountable] the ability to plan something and work successfully to achieve it
Synonym
determination
He has enormous confidence and strength of purpose.
see also cross purposes
Idioms

on purpose

not by accident; deliberately
He did it on purpose, knowing it would annoy her.

to little/no purpose

(formal) with little/no useful effect or resultThe government had spent a lot on education but to little or no purpose.
more at to all intents and purposes at intent n., for (all) practical purposes at practical adjective
Usage noteUsage note: purposeaim intention plan point ideaThese are all words for talking about what somebody/something intends to do or achieve.purpose what something is supposed to achieve; what somebody is trying to achieve:Our campaign's main purpose is to raise money.aim what somebody is trying to achieve; what something is supposed to achieve:She went to London with the aim of finding a job. Our main aim is to increase sales in Europe.purpose or aim?Your purpose for doing something is your reason for doing it; your aim is what you want to achieve. Aim can suggest that you are only trying to achieve something; purpose gives a stronger sense of achievement being certain. Aim can be somebody's aim or the aim of something. Purpose is more usually the purpose of something: you can talk about somebody's purpose but that is more formal.intention what you intend to do:I have no intention of going to the wedding. She's full of good intentions but they rarely work out.plan what you intend to do or achieve:There are no plans to build new offices.intention or plan?Your intentions are what you want to do, especially in the near future; your plans are what you have decided or arranged to do, often, but not always, in the longer term.point (rather informal) the purpose or aim of something:What's the point of all this violence? The point of the lesson is to compare the two countries.idea (rather informal) the purpose of something; somebody's aim:The whole idea of going was so that we could meet her new boyfriend. What's the idea behind this?point or idea?Point is a more negative word than idea. If you say What's the point…? you are suggesting that there is no point; if you say What's the idea…? you are genuinely asking a question. Point, but not idea, is used to talk about things you feel annoyed or unhappy about:There's no idea in… I don't see the idea of….with the purpose/aim/intention/idea of doing somethingsomebody's intention/plan to do somethingto have a(n) purpose/aim/intention/plan/pointto achieve/fulfil a(n) purpose/aim