That Siddha (liberated soul), who had attained emancipation prior to the establishment of the fourfold Tirtha (religious order established by the Tīrthankara (ford-founder)) or in the absence of Tirtha.
atitthaṃ - cātuvaṇṇasaṃghassa abhāvo titthakālabhāvassa vā abhāvo. tammi atitthakālabhāve atitthakālabhāvāto vā je siddhā te atitthasiddhā.
(Nandī 31 Cū p.26)