While holy, healthy, and whole have the same Germanic root, in Latin these concepts are denoted by words with different roots: sacer, sānus, and totus, from which we get sacred and sanctuary, sane and sanity, and total and totality, respectively.
Relating the first and last of these, we can view the Totality of Existence as sacred, that is holy. From this holistic perspective, the creative power of Life can heal our fragmented minds and split psyches—introjected from our sick society—in Wholeness, where all arts, humanities, and sciences are unified.
About 1380, sacrid, from past participle of sacren ‘to make holy, consecrate, sanctify’ (before 1200), from Old French sacrer ‘consecrate, anoint, dedicate’ or directly from Latin sacrāre ‘to make sacred, consecrate; hold sacred; immortalize, make inviolable; set apart, dedicate to a god’, from sacer ‘sacred, dedicated, holy; accursed, devoted to destruction’, related to sacra ‘religious rites’, from PIE base *sak-.