TOXOID
anatoxin, toxoid
(noun) a bacterial toxin that has been weakened until it is no longer toxic but is strong enough to induce the formation of antibodies and immunity to the specific disease caused by the toxin; “diphtheria toxoid”
Source: WordNet® 3.1
Etymology
Noun
toxoid (plural toxoids)
A toxin that has had its toxic properties removed, but retains its ability to generate an immune response.
Source: Wiktionary
Tox"oid, n. [Toxin + -oid.] (Physiol. Chem.)
Definition: An altered form of a toxin, possessing little or no toxic
power.
Source: Webster’s Unabridged Dictionary 1913 Edition