These groups are known as Greek letter societies or as being part of the Greek system.

VOA: special.2009.09.25

This isn't big Oh as in oh my God I'm shocked the markets are collapsing, This is called big Oh omicron because we use the Greek letter, capital letter, omicron to represent it.

我的天那，我的买卖砸了“,而是因为,我们用了希腊字母,大写的，来代表这种方法。

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