Of the core dimensions of this model, the one that would best be used to make job activities more meaningful would be the task significance. This is the dimension of a job that depends on how much the employee thinks the work they are doing is meaningful to the overall goal of the organization.
One example of this could be library work at a large university. A person who is in charge of putting materials on reserve for classes will likely feel that their activities are meaningful. They know that the professor wants those materials on reserve and they know that the students will be coming to get the materials in large numbers. This makes it clear to the worker that their task truly is meaningful.
The more significant the task is to the organization's goals, the more meaningful it will seem to the employee.