先来了解一下什么是融资轮：

融资轮/X轮融资指的是一个企业的资金筹集的行为与过程，一般情况顺序为天使投资，A轮（1轮）融资，B轮（2轮）融资，C轮（3轮）融资等。

涉及这一定义时，常见的关于“轮”的表达一般有两个，“round”和“series”。那么关于这两个，到底哪个更常用呢？先来看一下它们的英文解释：

（有关各轮融资的英文解释）

融资轮-funding round

A funding round is a monetary investment raised for a company or organization, usually funded by multiple individuals or entities. Funding rounds can be used for business acquisitions, expansions, operation expenses, and more.

种子前轮-pre-seed round

Pre-seed rounds are used to fund startups in their very first stages. Pre-seed funding rounds are often unreported because they are usually funded by the company founders or their personal acquaintances; this also means equity is not usually exchanged at this stage.

种子轮-seed round

Seed rounds are the first official equity funding stage that are reported. As seed funding is used to help companies establish their businesses, the funding can be used to pay for market research and product development. Seed rounds are sometimes funded by angel investors or venture capital firms. Depending on the company's valuation, seed round amounts can range from tens of thousands to millions of dollars.

天使轮-angel round

Angel rounds are funded by angel investors. Angel funding rounds are awarded in the early stages of a company, most often in exchange for equity.

A轮融资-Series A funding round

Series A funding rounds occur after the company is better established, such as by reporting consistent revenue or a steady user base. Series A rounds are usually valued in the millions—the median reported funding for a series A round in 2021 was $10 million. At this stage, larger investors are more likely to be involved in funding rounds.

B轮融资-Series B funding 

Series B funding is similar to series A. Once this stage has been reached, the company is typically ready to move past the original development phase and uses the funds to further production or service offerings. These rounds are valued in the tens of millions, with 2021's reported median being $40 million.

由以上英文释义可以得出，“轮”在这里是量词，对应的英文为“round”，如种子轮seed round、天使轮angel round；但涉及A轮融资、B轮融资这一阶段的融资时，除了最后的round之外，

又使用了特定的“series”来表示，因而“A轮融资”一般较少使用“Round A financing”，而应该是“Series A funding round”。

再参考维基百科中的定义：

Series A financing (also known as series A round or series A funding) is one of the stages in the capital-raising process by a startup. Essentially, the series A round is the second stage of startup financing and the first stage of venture capital financing.

可以发现round其实可以略去，Series A financing =series A round或series A funding。

因而，可以得出，round和series都可以作为“轮”使用，但适用情况各不相同。除了A轮融资、B轮融资等字母+轮融资（这类融资中使用Series A作为Series A round的简称）之外，“轮”作为普通量词使用时，包括在进行通用表述（三轮融资等表述）时均应使用round，而不得使用series。