holding device means "a device for holding something".
Is holding device a common word?
holding device is banded "Rare" — specialist or archaic — most readers will not have met it. The band comes from how often the word appears in a large corpus of everyday English, not from an editor's impression.
Definitions, synonyms and semantic relations for holding device come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.