I have a controversy of my project's leader about the meaning of "sub-project". When we need to translate sub-project from English to our native language (Vietnamese), I think that we should understand it as child project, as subsets in mathematics, because without the mother project, that sub-project has no significant role in our program. However, in her opinion, it should be translate literally to support project, since without it, the main project's result become less significant. In other words, I define the word by its role to the whole program, she defines it by its role to the main project.
There is no definition for this word in famous dictionaries like Oxford or Merriam-Webster, except Collins dictionary:
a project that is part of a larger project
This doesn't help. Which meaning is better for sub-project, "support project" or "child project"?