"pillars of activities" is a correct and usable phrase in written English.
You can use it when talking about activities that form the core or foundation of a certain project, program, or organization. For example: "These pillars of activities – storytelling, problem-solving, and art-making – are at the heart of our educational program."
We're moving forward with four major pillars of activity.
Our Center strives to achieve our mission through three key pillars of activity: research, education, and multi-disciplinary collaboration.
Our Center strives to achieve our mission through four pillars of activity: education, outreach, clinical programs, and research.
Three main ideas were the pillars of the development activities: the reduction of the geometrical filament size down to 2 μm, the use of CuMn resistive barriers to reduce the inter filament coupling currents, and the reduction to the minimum allowable value of the twist pitch.
And how would that change our perspective on likely economic behavior around three major pillars of U.S. economic activity: housing, autos and finance?
The evidence has reached critical mass getting between seven and nine hours of sleep a night is one of the pillars of good health, along with physical activity and eating a healthful diet.
Cleaning up these onsite errors won't immediately send you to a higher position in search engines, but it will make it easier for you to do so once you implement a long-term strategy of recurring content, offsite links, and social media activity; the three pillars of SEO.
Such crafts activities, "working," are essential pillars of the care and attention Hope House residents receive, in addition to tending to plant beds, participating in outings, games and other stimulating activities -- even a Christmas "5K" event.
> Global public health surveillance is an essential activity promoted under the IHR (2005) agenda [ 23], as well as one of the pillars of the Global Polio Eradication Initiative.
"Seven Pillars of Wisdom".
