'Jury mast' definitions:

Definition of 'jury mast'

(from WordNet)
noun
A temporary mast to replace one that has broken off

Definition of 'Jury mast'

From: GCIDE
  • Jury mast \Ju"ry mast\ (a) A temporary mast, in place of one that has been carried away, or broken. (b) (Med.) An apparatus to support the trunk and head in spinal disease. [Webster 1913 Suppl.]