Indispensable evidence
Defined in 2 dictionaries — Ballentine's (1916), Black's (1910)
Ballentine's Law Dictionary
James A. Ballentine · 1916
Evidence without which a certain fact cannot be proved.
Black's Law Dictionary
Henry Campbell Black, M.A. · 1910
That without which a particular fact cannot be proved. Code Civ. Proc. Cal. 1903, § 1836; Ballinger's Ann. Codes & St. Or. 1901, § 689
Defined under Evidence in Black's Law Dictionary.