submission date; filing date; due date
Refers to the date something must be submitted, such as homework, applications, or documents. Often used in academic, administrative, and business contexts.
The submission date for the report is next Friday.
If you miss the due date, it won't be accepted.
期限 is a broader term for a time limit or deadline, not necessarily tied to submitting something.
Compound of 提出 (ていしゅつ, 'submission') and 日 (び, 'day').