1. Size, mass, or volume, especially when very large.
2.
a. A distinct mass or portion of matter, especially a large one: the dark bulk of buildings against the sky.
b. The body of a human, especially when large or muscular.
3. The major portion or greater part: "The great bulk of necessary work can never be anything but painful" (Bertrand Russell).
4. See fiber.
5. Thickness of paper or cardboard in relation to weight.
6. A ship's cargo.
v.bulked, bulk·ing, bulks