¦ā(ˌ)chelˈā noun
( -s )
Usage: often attributive
Etymology: h uman l eukocyte a ntigen
1. : the major histocompatibility complex in humans
2. : a genetic locus, gene, or antigen of the human major histocompatibility complex — often used with one or more letters to designate a locus or with such letters and a number to designate an allele at the locus or the antigen of the major histocompatibility complex corresponding to the locus and allele