noun
Refers to an object that is old and valued for its age, often with historical or collectible appeal. Used for furniture, art, books, etc.
この店には年代物の家具がたくさんある。
This shop has a lot of antique furniture.
彼は年代物の腕時計
He collects vintage watches.
骨董品 specifically refers to art objects or curios of high artistic or historical value, whereas 年代物 is a broader term for any old item that has aged well.
Compound of 年代 (age, era) and 物 (thing). The word literally means 'thing of an era', referring to an item that has survived from a past period.