The Collaborative International Dictionary of English v.0.48:

Tabloid \Tab"loid\, n. [A table-mark.]
   1. A compressed portion of one or more drugs or chemicals, or
      of food, etc.
      [Webster 1913 Suppl.]

   2. a newspaper with pages about half the size of a
      standard-sized newspaper, especially one that has
      relatively short or condensed articles and a large
      porortion of pictorial matter.
      [PJC]

The Collaborative International Dictionary of English v.0.48:

Tabloid \Tab"loid\ (t[a^]b"loid), a.
   1. Compressed or condensed, as into a tabloid; administrated
      in or as in tabloids, or small condensed bits; as, a
      tabloid form of imparting information.
      [Webster 1913 Suppl.]

   2. of or pertaining to a tabloid newspaper or the type of
      story typically contained in one, such as lurid or
      sensationalistic stories of scandal, crime, or violence.
      [PJC]

WordNet (r) 3.0 (2006):

tabloid
    n 1: sensationalist journalism [syn: yellow journalism,
         tabloid, tab]
    2: newspaper with half-size pages [syn: tabloid, rag,
       sheet]