Key Difference: The way the word is spelled depends on the where and by whom the text was written. British English (the more popular) uses the spelling ‘labour’, while American English did not see the reason for the ‘u’ and use the spelling ‘labor’. Both the words mean the exact same thing.

The terms labor and labour are often confusing for many people that are learning English as a second language. The reason for this confusion stems from the many texts that use the word labor, while others use labour. Neither of the spelling is wrong, both are used appropriately. They can also be easily interchanged without changing the connotation of the sentence.

The way the word is spelled depends on the where and by whom the text was written. British English (the more popular) uses the spelling ‘labour’, while American English did not see the reason for the ‘u’ and use the spelling ‘labor’. Both the words mean the exact same thing.

The term labor/labour is defined as a noun as well as a verb. It can be used either way. Merriam Webster defines the term in the following manner.

Labor/Labour (Noun):

• expenditure of physical or mental effort especially when difficult or compulsory
• human activity that provides the goods or services in an economy
• the services performed by workers for wages as distinguished from those rendered by entrepreneurs for profits
• the physical activities (as dilation of the cervix and contraction of the uterus) involved in giving birth; also :  the period of such labor
• an act or process requiring labor; task
• a product of labor
• an economic group comprising those who do manual labor or work for wages; (1) workers employed in an establishment (2) workers available for employment
• the organizations or officials representing groups of workers

The term ‘Labour’ and not Labor can also refer to the Labour party of the United Kingdom or other Commonwealth Nations.

Labor/Labour (Verb)

• to exert one's powers of body or mind especially with painful or strenuous effort; work
• to move with great effort
• to be in the labor of giving birth
• to suffer from some disadvantage or distress

Both the terms are similar in spelling as well as connotations. There are only few occasions where both the words refer to different things. Hence, in most cases they can be used interchangeably.

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