In chemistry, on Earth in gravity, if a material from solution conformally, over all surfaces vertical and horizontal (e.g. the sides as well as the bottom of a container) is that still sometimes considered precipitation? Or is that crystallization from solution, and analogous to frost formation but not snow or rain?
Precipitation, as typically used an understood in chemistry, is really a very very old terminology (~ several hundred years). It refers to the formation of a solid by adding or mixing chemical reagents or even by cooling. There is no such requirement that the precipitate has to settle to the bottom. For example, colloids may not settle for ages. Precipitation involves crystallization, but not all precipitates are crystals (organic substances can be precipitated out by adding suitable solvents to a solution).
Now there are special ways to generate precipitates in solution. There was an experiment which we taught in classical analysis. The experiment goes like this. Add urea to an iron salt. No precipitate forms and there are no seeds to begin with. Let it boil slowly. With the passage of time, the entire solution becomes basic and it would uniformly produce precipitate iron hydroxide. Since it was a in situ chemical decomposition of urea to produce iron hydroxides in solution, this process occurs very uniformly in the solution i.e., there is no localization where two reagent were being mixed. This yielded uniformly sized particles. Such a process is called homogeneous precipitation in solution. Contrast this situation where we would add NaOH solution to iron salts. It will be impossible to avoid localized mixing.
Meterologists use the term precipitation as well, but as per the unabridged Oxford Dictionary (can't provide a link as it is by subscription), the full word is atmospheric precipitation.
In case you are interested, the etymology is
Etymology: < classical Latin praecipitāt-, past participial stem (see
-ate suffix3) of praecipitāre to throw or cause to fall headlong, to ruin, destroy, to fall headlong, to suffer ruin, come to grief, to
hasten, to rush, in post-classical Latin also to cause to be deposited
as a solid from a liquid solution (a1490, 1652 in British sources) <
praecipit- , praeceps (adjective) headlong, sheer (see precipe n.).
Compare Middle French, French precipiter , précipiter precipit v.
