n.
Pronunciation: vak- ' si-n ē - ə
Function: noun
Etymology: New Latin, from vaccinus
Date: 1803
1 : a poxvirus (species Vaccinia virus of the genus Orthopoxvirus ) that differs from but is closely related to the viruses causing smallpox and cowpox and that includes a strain of uncertain natural origin used in making vaccines against smallpox ― called also vaccinia virus
2 : a reaction to smallpox vaccine prepared from live vaccinia virus that may involve a rash, fever, headache, and body pain
– vac · cin · i · al \ -n ē - ə l \ adjective