verb
To substantiate is to prove a claim to be true or back up a claim with evidence.
When you do a research project to prove a scientific theory, this is an example of a situation where you substantiate the theory.
substantiate

transitive verb
-·at·ed, -·at·ing- to give substance or true existence to
- to give concrete form or body to; convert into substance; embody
- to show to be true or real by giving evidence; prove; confirm
Origin of substantiate
from Modern Latin substantiatus, past participle of substantiare from Classical Latin substantia, substancesubstantiate

transitive verb
sub·stan·ti·at·ed, sub·stan·ti·at·ing, sub·stan·ti·ates- To prove the truth of or support with proof or evidence: substantiate an accusation. See Synonyms at confirm.
- To give substance to; make real or actual.
Origin of substantiate
New Latin substantiāre substantiāt- from Latin substantia substance ; see substance .Related Forms:
- sub·stan′ti·a′tion
noun
substantiate

Verb
(third-person singular simple present substantiates, present participle substantiating, simple past and past participle substantiated)
- to verify something by supplying evidence; to corroborate or authenticate
- to give material form or substance to something; to embody