To solidify or take on a gelatinous consistency, or, figuratively, to take shape, become definite, or coalesce.
It can refer to physical substances thickening, or abstract ideas, plans, or relationships becoming clear and well-defined.
When referring to plans or ideas, it implies a process of refinement and agreement, resulting in a cohesive and workable form.
The core meaning centers on the process of becoming structured or taking a firm form, whether literally or metaphorically.
Jelling can also suggest a sense of coming together, where the individual elements of a group, substance, or system are merging into a unified whole.
SET
CONGEAL
SOLIDIFY
CRYSTALLIZE