Grex or GREX may refer to:
*
Grex (biology), a multicellular aggregate of amoeba of the phyla Acrasiomycota or Dictyosteliomycota
*
Grex (horticulture), (pl. greges) a kind of group used in horticultural nomenclature applied to the progeny of an artificial cross from specified parents
* Formerly used to mean
species aggregate
*
Georgetown Rail Equipment Company
The Georgetown Rail Equipment Company (GREX) is a provider of railway maintenance equipment and related services based in Georgetown, Texas. The company was founded in 1993 and is often referred to using the abbreviation GREX, also used for its ...
, a provider of railway maintenance equipment and related services based in Georgetown, Texas
{{disambiguation