Size, specifically, volume.

Any huge body or structure.

The noun "bulk" represents the major part or majority of something.

(intransitive) To appear or seem to be, as to bulk or extent.

(intransitive) To grow in size; to swell or expand.

(intransitive) To gain body mass by means of diet, exercise, etc.

(transitive) To put or hold in bulk.

being large in size, mass or volume (of goods, etc.)

total