卵子 ova

The Japan Newsにあった卵子提供に関する記事から。記事にもあるように「卵子」はeggという簡単な言い回しに加えて，見出しにあるようにova（単数形はovum）とも言います（『プログレッシブ英和中辞典』小学館）。
また言うまでもないかもしれませんが，「楕円形の」を表すovalはこのovumに由来するものです。（Koyamamoto）

3 women to receive ova via NPO
Three women suffering from infertility due to chromosomal abnormalities or other conditions will receive ova donated through an intermediate nonprofit organization, the first such case in the country.
Although some medical institutions use eggs donated from patients' sisters or acquaintances, there have been no cases of using eggs donated through a third-party to date.
The Kobe-based NPO, the Oocyte Donation Network (OD-NET), comprises doctors, patient supporters and others. It provides eggs from third-party donors to women unable to become pregnant with their own eggs.
http://the-japan-news.com/news/article/0000225497