1. Unpackaged; loose.
2. In large numbers, amounts, or volume.
To gain weight by gaining muscle: dietary supplements that helped the weightlifters bulk up.
Being large in mass, quantity, or volume: a bulk buy; a bulk mailing.
1. Size, mass, or volume, especially when very large.
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.http://www.thefreedictionary.com/bulk