[W/K] :: Rain water

  Rain \Rain\ (r[=a]n), n. [OE. rein, AS. regen; akin to OFries.
     rein, D. & G. regen, OS. & OHG. regan, Icel., Dan., & Sw.
     regn, Goth. rign, and prob. to L. rigare to water, to wet;
     cf. Gr. bre`chein to wet, to rain.]
     Water falling in drops from the clouds; the descent of water
     from the clouds in drops.
     [1913 Webster]
  
           Rain is water by the heat of the sun divided into very
           small parts ascending in the air, till, encountering
           the cold, it be condensed into clouds, and descends in
           drops.                                   --Ray.
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           Fair days have oft contracted wind and rain. --Milton.
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     Note: Rain is distinguished from mist by the size of the
           drops, which are distinctly visible. When water falls
           in very small drops or particles, it is called mist;
           and fog is composed of particles so fine as to be not
           only individually indistinguishable, but to float or be
           suspended in the air. See Fog, and Mist.
           [1913 Webster]
  
     Rain band (Meteorol.), a dark band in the yellow portion of
        the solar spectrum near the sodium line, caused by the
        presence of watery vapor in the atmosphere, and hence
        sometimes used in weather predictions.
  
     Rain bird (Zool.), the yaffle, or green woodpecker. [Prov.
        Eng.] The name is also applied to various other birds, as
        to Saurothera vetula of the West Indies.
  
     Rain fowl (Zool.), the channel-bill cuckoo ({Scythrops
        Novae-Hollandiae) of Australia.
  
     Rain gauge, an instrument of various forms for measuring
        the quantity of rain that falls at any given place in a
        given time; a pluviometer; an ombrometer.
  
     Rain goose (Zool.), the red-throated diver, or loon. [Prov.
        Eng.]
  
     Rain prints (Geol.), markings on the surfaces of stratified
        rocks, presenting an appearance similar to those made by
        rain on mud and sand, and believed to have been so
        produced.
  
     Rain quail. (Zool.) See Quail, n., 1.
  
     Rain water, water that has fallen from the clouds in rain.
        [1913 Webster]

  RAIN WATER. The water which naturally falls from the clouds. 
       2. No one has a right to build his house so as to cause the rain water 
  to fall over his neighbor's land; 1 Rolle's Ab. 107; 2 Leo. 94; 1 Str. 643; 
  Fortesc. 212; Bac. Ab. Action on. the case, F.; 5 Co. 101; 2 Rolle, Ab. 565, 
  1. 10; 1 Com. Dig. Action upon the case for a nuisance, A; unless he has 
  acquired a right by a grant or prescription. 
       3. When the land remains in a state of nature, says a learned writer, 
  and by the natural descent, the rain water would descend from the superior 
  estate over the lower, the latter is necessarily subject to receive such 
  water. 1 Lois des Batimens, 15, 16. Vide 2 Roll. 140; Dig. 39, 3; 2 Bouv. 
  Inst. n. 1608.