Of an allele or phenotype, the naturally occurring, unaltered, or most frequent; if several alleles occur, the most frequent one is considered to be the wild type.
Source:
PAC, 2016, 88, 713. 'Glossary of terms used in developmental and reproductive toxicology (IUPAC Recommendations 2016)' on page 821 (https://doi.org/10.1515/pac-2015-1202)