The Collaborative International Dictionary of English v.0.48:

Heredity \He*red"i*ty\, n. [L. hereditas heirship.] (Biol.)
   Hereditary transmission of the physical and psychical
   qualities of parents to their offspring; the biological law
   by which living beings tend to repeat their characteristics
   in their descendants. See Pangenesis.
   [1913 Webster]

WordNet (r) 3.0 (2006):

heredity
    n 1: the biological process whereby genetic factors are
         transmitted from one generation to the next
    2: the total of inherited attributes [syn: heredity, genetic
       endowment]

Moby Thesaurus II by Grady Ward, 1.0:

60 Moby Thesaurus words for "heredity":
   Altmann theory, DNA, DNA double helix, De Vries theory,
   Galtonian theory, Mendelianism, Mendelism, RNA, Verworn theory,
   Weismann theory, Weismannism, Wiesner theory, allele, allelomorph,
   anticodon, biotype, birth, character, chromatid, chromatin,
   chromosome, codon, deoxyribonucleic acid, determinant, determiner,
   diathesis, endowment, eugenics, factor, gene, gene complex,
   gene flow, gene pool, genesiology, genetic code, genetic drift,
   genetics, genotype, hereditability, hereditary character,
   heritability, heritage, inborn capacity, inheritability,
   inheritance, mRNA, matrocliny, messenger RNA, nucleotide,
   operator gene, operon, patrocliny, pharmacogenetics,
   recessive character, regulator gene, replication, ribosomal RNA,
   structural gene, tRNA, transfer RNA