petitioner 是指：向美国公民及移民服务局（USCIS）申请家庭移民签证的家属，家属为美国公民或合法永久居民，或申请工作移民签证的雇主（或雇主委托人）

Petitioner:A U.S. citizen or lawful permanent resident family member or employer (or the employer's agent) who files a family-based or employment-based immigrant visa petition with USCIS.

 

Applicant （签证）是指：申请美国非移民签证或美国移民签证的外国公民，即签证申请书所指“受益人”。

Applicant (Visa): A foreign citizen who is applying for a nonimmigrant or immigrant U.S. visa. The visa applicant may also be referred as a beneficiary for petition based visas.