Source : Webster's Revised Unabridged Dictionary (1913)

Hemorrhoids \Hem"or*rhoids\, n. pl. [L. haemorrhoidae, pl., Gr.
   ?, sing., ? (sc. ?), pl., veins liable to discharge blood,
   hemorrhoids, fr. ? flowing with blood; a"i^ma blood + ? to
   flow: cf. F. h['e]morro["i]des, h['e]morrho["i]des. See
   {Rheum}.] (Med.)
   Livid and painful swellings formed by the dilation of the
   blood vessels around the margin of, or within, the anus, from
   which blood or mucus is occasionally discharged; piles;
   emerods.

   Usage: [The sing. {hemorrhoid} is rarely used.]

Source : WordNet®

hemorrhoid
     n : pain caused by venous swelling at or inside the anal
         sphincter [syn: {haemorrhoid}, {piles}]