1. To change into another substance. 'The spider love which transubstantiates all, And can convert manna to gall.' (Donne) ... 2. To change, as the sacramental elements, bread and wine, into the flesh and blood of Christ. ... Origin: LL. Transubstantiatus, p. P. Of transubstantiare to transubstantiate; L. Trans across, over + substantia substance. ... Found on http://www.encyclo.co.uk/local/20973