properdin
noun
pro·per·din prō-ˈpər-dᵊn 
: a blood serum protein that participates in the activation of complement in a pathway which does not involve the presence of antibodies
Word History
Etymology
probably from pro- entry 1 + Latin perdere to destroy + English -in entry 1 — more at perdition
First Known Use
1954, in the meaning defined above
Medical Definition
properdin
noun
pro·per·din prō-ˈpərd-ᵊn
: a blood serum protein that participates in the activation of complement in a pathway which does not involve the presence of antibodies