Refers to decorative raised carving or embossing on surfaces such as metal, leather, or wood. A technical craft term.
This silverware has beautiful relief work applied to it.
革の表紙に彫り上げ細工で模様を付ける。
A pattern is added to the leather cover by embossing.
浮き彫り is a more common term for relief or embossing, while 彫り上げ細工 is a specific compound often used in traditional crafts.
細工 means 'workmanship' or 'craft' in general; 彫り上げ細工 specifies raised carving work.
Compound of 彫り上げ (ほりあげ, 'carving up' or 'raising by carving') and 細工 (ざいく, 'craftwork'). The exact historical derivation is uncertain, but the term is conventionally associated with raised decorative carving.