The Collaborative International Dictionary of English v.0.48:

yelling \yell"ing\, n.
   The uttering of one or more loud inarticulate cries, as of
   pain or excitement.

   Syn: shouting.
        [WordNet 1.5]

The Collaborative International Dictionary of English v.0.48:

Yell \Yell\ (y[e^]l), v. i. [imp. & p. p. Yelled; p. pr. & vb.
   n. Yelling.] [OE. yellen, [yogh]ellen, AS. giellan, gillan,
   gyllan; akin to D. gillen, OHG. gellan, G. gellen, Icel.
   gjalla, Sw. g[aum]lla to ring, resound, and to AS., OS., &
   OHG. galan to sing, Icel. gala. Cf. 1st Gale, and
   Nightingale.]
   To cry out, or shriek, with a hideous noise; to cry or scream
   as with agony or horror.
   [1913 Webster]

         They yelleden as feendes doon in helle.  --Chaucer.
   [1913 Webster]

         Nor the night raven, that still deadly yells.
                                                  --Spenser.
   [1913 Webster]

         Infernal ghosts and hellish furies round
         Environed thee; some howled, some yelled. --Milton.
   [1913 Webster]

WordNet (r) 3.0 (2006):

yelling
    n 1: uttering a loud inarticulate cry as of pain or excitement
         [syn: yelling, shouting]

Moby Thesaurus II by Grady Ward, 1.0:

19 Moby Thesaurus words for "yelling":
   bawling, blatant, boanergean, brawling, clamorous, clamoursome,
   crying, loudmouthed, noisy, obstreperous, openmouthed, screaming,
   shouting, vociferant, vociferating, vociferous, yammering, yapping,
   yelping