To become congealed, solidify.
To change from a liquid to solid state, perhaps due to cold; called to freeze in nontechnical usage.
To coagulate, make curdled or semi-solid such as gel or jelly.
To make rigid or immobile.
To strengthen.
To become or make (a person or thing) resistant or less sensitive.
To become or make (a consonant) more fortis; to (cause to) undergo fortition.
To make something hard or harder (tough, resistant to pressure).
To modify (a website or other system) to make it resistant to malicious attacks.
To unpalatalize or velarize.
To become hard (tough, resistant to pressure).