What does "antigen" mean?

A substance that induces an immune response, usually foreign (nonself) but not always so.

Antigen

Common synonyms include: acquired immunity, active immunity, agglutinin, allergen, anaphylactin, antiantibody.

noun

noun ·3 syllables ·Moderate ·College level

Noun

1
A substance that induces an immune response, usually foreign (nonself) but not always so.
2
any substance (as a toxin or enzyme) that stimulates an immune response in the body (especially the production of antibodies) wordnet

"If you only have the B antigen, your blood is type B."

From French antigène, from anti- + gène.