The phrase "big project" refers to a task or assignment that requires a lot of time, effort, and resources to complete. It usually involves complex or important work that is significant in size or scope. Full definition
Most college students complete a number of big projects in school. (livecareer.com)
We have done so much work in this house, but I have mainly been working on big projects in different rooms and leaving the little stuff for later. (abbottsathome.com)
For big projects like writing an article, break it down the very next actionable step, such as choosing the topic. (slaw.ca)