so‧lid‧i‧fy past tense and past participle solidified, present participle solidifying, third person singular solidifies
1 [intransitive and transitive]
to become solid or make something solid:
The volcanic lava solidifies as it cools.
to make an agreement, plan, attitude etc more definite and less likely to change:
The two countries signed a treaty to solidify their alliance.
—solidification noun [uncountable]