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]

Moby Thesaurus II by Grady Ward, 1.0:

39 Moby Thesaurus words for "tabloid":
   daily, daily newspaper, even, extra, extra edition, flat,
   flattened, flush, gazette, homaloidal, horizontal, level, livid,
   lurid, national newspaper, neighborhood newspaper, news, newspaper,
   newspaper of record, paper, plain, plane, rag, rolled,
   sensationalistic, sheet, smooth, smoothed out, smoothened, special,
   special edition, squashed, squashed flat, sultry, tabular, trodden,
   trodden flat, weekly, weekly newspaper