Is there a word to describe a gathering lump of water hanging on a surface that has not yet produced a droplet? Imagine a small pool of water without the surface upon which it's resting.
I agree with camelbrush's answer, but I also thought of the less technical word of bead.
As a noun, bead means:
any small globular or cylindrical body, as a drop of liquid or a bubble in an effervescent liquid: beads of sweat.
As a verb, bead means:
to bead, to form into beads or drops
I think of a bead as a droplet forming, but before it drops as a droplet.
A drop or droplet is a small column of liquid, bounded completely or almost completely by free surfaces. A drop may form when liquid accumulates at the lower end of a tube or other surface boundary, producing a hanging drop called a pendant drop.
Also, there is an adjective: Pendent, which is used for anything hanging down.