O
noun /əʊ,oʊ/
a) A blood type that lacks A or B antigens and may only receive transfusions of similar type O blood, but may donate to all (neglecting Rh factor). Synonym: universal donor.
b) of octavo, a book size (20-25 cm).

Wikipedia foundation.

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”