noun
first-rate sword; excellent blade
Historical term used in Japanese sword appraisal to denote a blade of the highest quality, above 良業物 (good sword) and 業物 (sharp sword).
この刀は大業物と鑑定された。
This sword was appraised as a first-rate blade.
良業物 is a good-quality sword, ranking below 大業物 in traditional sword appraisal.
Compound of 大 (great) and 業物 (sharp sword). The exact historical derivation of 業物 is uncertain, but it is a traditional term in Japanese sword connoisseurship.