To substantiate is to prove a claim to be true or back up a claim with evidence.(verb)
When you do a research project to prove a scientific theory, this is an example of a situation where you substantiate the theory.
See substantiate in Webster's New World College Dictionary
See substantiate in American Heritage Dictionary 4
transitive verb sub·stan·ti·at·ed, sub·stan·ti·at·ing, sub·stan·ti·ates
Origin: New Latin substantiāre, substantiāt-
Origin: , from Latin substantia, substance; see substance.
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