initial public offering一般是指“首次公开发行；首次公开募股”

Investopedia中有对offering的详细解释：

An offering is the issue or sale of a security by a company. It is often used in reference to an initial public offering (IPO) when a company's stock is made available for purchase by the public, but it can also be used in the context of a bond issue.

An offering is also known as a securities offering, investment round, or funding round. A securities offering, whether an IPO or otherwise, represents a singular investment or funding round. Unlike other rounds (such as seed rounds or angel rounds), however, an offering involves selling stocks, bonds, or other securities to investors to generate capital.

参考译文：

发行是公司发行或出售证券。 当公司的股票可供公众购买时，其通常用于参考首次公开募股 (IPO)，但也可以用于债券发行的背景下。

发行也称为证券发行、投资轮或融资轮。 证券发行，无论是首次公开募股还是其他方式，均代表着单一的投资或融资轮次。 然而，与其他轮次（如种子轮或天使轮）不同的是，发行涉及向投资者出售股票、债券或其他证券以产生资金。