Also found in: Thesaurus, Encyclopedia, Wikipedia.


A form of matter hypothesized by proponents of the Big Bang theory to have existed before the formation of the chemical elements.

[Middle English, universal matter, from Old French ilem, from Medieval Latin hȳlem, accusative of hȳlē, matter, from Greek hūlē.]


(Astronomy) the original matter from which the basic elements are said to have been formed following the explosion postulated in the big bang theory of cosmology
[Middle English, from Old French ilem, from Latin hӯlē stuff, matter, from Greek hulē wood, matter]
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.ylem - (cosmology) the original matter that (according to the big bang theory) existed before the formation of the chemical elements
matter - that which has mass and occupies space; "physicists study both the nature of matter and the forces which govern it"
cosmogeny, cosmogony, cosmology - the branch of astrophysics that studies the origin and evolution and structure of the universe
References in periodicals archive ?
emerges as a sign of life in Ylem (1972), a musical fable depicting, in a mere twenty-six minutes, the expansion and contraction of our universe and its renewed expansion thereafter in an alternate space-time outside the concert chamber.
Gamow adopted the word ylem (pronounced eye-lem), an ancient word meaning primordial substance, for the stuff from which the universe was made.
Antibodies and antisera employed Antibody or Antiserum P or M (clone)(*) Dilution Mitochondrion M (113-1) 1/100 Thyroglobulin P Undiluted Carcino-embryonic antigen M (B01-94-11M) Undiluted Calcitonin M (SILVIA) 1/200 Chromogranin A M (Phe 5) 1/50 Prostatic specific antigen P Undiluted Pepsinogen II P 7/2000 E-cathepsin P 1/2000 Salivary amylase P 1/100 Ki-67 M (MIB-1) 1/50 p53 M (DO7) 1/1000 Antibody or Antiserum Source Mitochondrion BioGenex, San Ramon, Calif Thyroglobulin Ortho, Raritan, NJ Carcino-embryonic antigen BioGenex Calcitonin Ortho Chromogranin A Enzo, New York, NY Prostatic specific antigen Dako, Copenhagen, DK Pepsinogen II Gift of Samloff([dagger]) E-cathepsin Gift of Samloff([dagger]) Salivary amylase Biogensis, Bournemouth, UK Ki-67 Ylem, Roma, I p53 Dako