proprietorship的英文释义如下：the fact or state of being the owner of a business, a hotel, etc.根据这一定义，该词汇仅表示拥有一家企业的状态，而不强调 sole ownership.

在法律英语中，sole proprietorship means ventures exclusively with one's own investment; solely foreign-owned enterprise; sole [exclusively] foreign-invested project [enterprise]; enterprise owned by a sole investor。

因此，独资企业只用 proprietorship 一个词并不足以表示其中文含义，用 sole proprietorship 更为妥帖。

我也找到了一些 sole proprietorship 的相关例句供佐证参考：

1.

Although it is specified in CEPA IV that local companies are allowed to operate as a soleproprietorship to provide software facilities, consultancy services and data services in the Mainland, enterprises solely owned by Hong Kong businessmen are regarded as foreign businesses according to the Company Law of the Mainland.

CEPA IV 虽已容许本地公司在内地设立独资企 业提 供软 件设施、顾问服 务和数据服务等，但按内地《公司法》，港商在内地的独资企业仍属外商。 

2.

To provide information on the number of unincorporated businesses, notably small and medium sized businesses under sole proprietorship, which would benefit from the proposed lowering of the standard rate.

 提供资料，说明将可受惠于调低标准税率的建议的非法团企业( 特别是独资经营的中小型企业)数目。 

3.

Although health care services providers of Hong Kong can set up out-patient clinics in soleproprietorship in Guangdong Province under the framework of CEPA, in-patient services are excluded. 

虽然在 CEPA的框架下，香港的医疗服务提供者已可在广东 省 以独 资形 式设立 门诊部，但不包括住院服务在内。