tran·sub·stan·ti·ate 
(trăn′səb-stănshē-āt′)
(trăn′səb-stănshē-āt′)tr.v. tran·sub·stan·ti·at·ed, tran·sub·stan·ti·at·ing, tran·sub·stan·ti·ates
1. To change (one substance) into another; transmute.
2. Christianity To change the substance of (the Eucharistic bread and wine) into the body and blood of Jesus.
[Medieval Latin trānsubstantiāre, trānsubstantiāt- : Latin trāns-, trans- + Latin substantia, substance; see SUBSTANCE.]