genotype UK /ˈdʒɛnəʊˌtaɪp/US /ˈd͡ʒinoʊˌtaɪp/noun 3verb 1forms 3 noun3 •The part (DNA sequence) of the genetic makeup of an organism which determines a specific characteristic (phenotype) of that organism. •A group of organisms having the same genetic constitution. •(no longer used) The type species of a genus; generitype. verb1 •To determine the genotype of. formsgenotyped · genotyping · genotypes