你应该在词典里查 small fry，而不只是查 fry。

small fry  people or things that are not important when compared to other people or things （相比之下的）小人物，小事情

你的句子意思是：However, that was small fry compared with the city’s Circus Maximus, which accommodated around 250,000 people. 然而，与可容纳约250,000人的城市马戏团马克西姆斯体育场相比，这只是小巫见大巫。

更多例句如：

There’s no point in arresting the small fry. 逮捕这些小卒子是毫无意义的。

Big businesses are not concerned with the small fry. 大企业不关注鸡老蒜皮命小事。

They’re small fry compared to the real criminals. 比起真正的罪犯他们是小卒子。

People like us are small fry to such a large business. 对于这样一家大公司来说，我们这样的人不过是小鱼小虾。

注意该词通常用单数，但表示复数意义。如：

It’s the small fry who are usually the last to get paid. 小人物往往是最后才拿到酬金。

The small fry are helping each other compete against the larger businesses. 小企业正在互相帮助来与大企业抗衡。

High-ranking officials escaped prosecution while numerous small fry were imprisoned. 高官们逃脱了起诉而很多无足轻重的人却入狱了。