It is your principal means of keeping up morale among the volunteers.

By the late 6th century, the principal means of religious instruction in the Church had become music and art rather than the book.

Thus, it was the principal means of deterrence from 1948 to the late 1950s.

They are the principal means of transportation in many regions.

The principal means of financing construction was through building societies.

Freedom in this sense becomes "the primary end" and "the principal means of development."

In the past week, she had become a principal means of support for her community.

Indeed, they are the principal means of identifying almost all serious American wines.

Art is the only method we have for stopping time, so it's our principal means of coming to terms with history.

The system is the central bank's principal means of transferring money between banks.