muniment

n. [ L. munimentum, fr. munire to fortify. See Munition. ] 1. The act of supporting or defending. [ Obs. ] [ 1913 Webster ]

2. That which supports or defends; stronghold; place or means of defense; munition; assistance. “Other muniments and petty helps.” Shak. [ 1913 Webster ]

3. (Law) A record; the evidences or writings whereby a man is enabled to defend the title to his estate; title deeds and papers. Blount. [ 1913 Webster ]

Muniment room or
Muniment house, that room in a cathedral, castle, or other public building, which is used for keeping the records, charters, seals, deeds, and the like. Gwilt. [ 1913 Webster ]