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English definition of “main”

main

adjective [before noun] uk   /meɪn/ us  
B1 larger, more important, or having more influence than others of the same type: The main thing is not to worry. One of the main reasons I came to England was to study the language. You'll find the main points of my proposal in the report. Our main aim/objective is to improve the company's productivity. The main problem in the health service is lack of resources. My main concern about moving to London is the cost of housing.Very important or urgent

main

noun uk   /meɪn/ us  

main noun (PIPE)

[C] a large pipe that carries water or gas, or a wire carrying electricity, from one place to another, to which a house can be connected: a gas main The severe cold caused a water main to burst and flood the street.Plumbing and pipes and sewageElectrical components and circuitry mains [plural] UK the system of pipes or wires that carry water or electricity into a house, or the pipes that carry sewage away from a house: The house isn't on the mains. They bought a house with no mains supply. mains electricityPlumbing and pipes and sewageElectrical components and circuitry the mains UK the place at which outside pipes or wires carrying water, electricity, etc. connect with the system inside a house or building: Switch off the electricity at the mains before starting work.Plumbing and pipes and sewageElectrical components and circuitry

main noun (MOSTLY)

in the main generally or mostly: Her friends are teachers in the main.ImportanceUseful or advantageous
(Definition of main from the Cambridge Advanced Learners Dictionary & Thesaurus © Cambridge University Press)
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