The phrase "a major source of support" is correct and usable in written English.
You can use it when discussing something or someone that provides significant assistance or help in a particular context.
Example: "The community center has become a major source of support for local families in need."
Alternatives: "a key source of assistance" or "a primary source of help."
Party organizations are often a major source of support for incumbents.
In the run-up to the general election, a major source of support for Ukip came from those Conservative and Labour voters who felt left behind by a new world of internationalised free trade.
Broomfield is attending Sheffield, he says, as a favour to C4 and, more particularly, to outgoing chief executive Michael Jackson, who has been a major source of support and finance.
Their own schooling experiences can also be a major source of support – a significant factor that is most often ignored within studies on school success by children of immigrants and second-generation Turks in particular.
Once this quantitative easing program ends, the economy will be missing a major source of support.
Those dollars have been a major source of support for community-organizing groups throughout the country.
Garrett's comments also cost him support from Wall Street donors, a major source of funding for his campaign.
"– HIV-negative postpartum Even when the partner continued to play a role in the young woman's life, the woman's family was still the primary source of financial support and a major source of emotional support.
Among the support options available, volunteer-led, community-based face-to-face prostate cancer support groups (PCSGs) have prevailed as a major source of such support in Canada for more than 20 years, attracting men and their partners to monthly meetings at approximately 100 Canadian groups.
If used wisely, EU funds such as the European social fund can be a major source of financial support, together with the European Investment Bank.
Various studies suggest that siblings are a major source of educational support in large families (Vanhée, Bois, Henri-Panabière, Court, Bertrand, 2013), and more in immigrant families than in non-immigrant families (Moguérou and Santelli 2012).
