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 confirm.
To become thicker (in the sense of wider).
To become thicker (in the sense of more viscous).
To make thicker (in the sense of more viscous).
To make thicker (in the sense of wider).
To make more frequent.