noun

• (uncountable, informal) Administration, or administrative work.
  "There's a lot of admin involved in the birth of a child."
• (countable, informal) An administration (a body that administers; the executive part of government).
  "Senate Minority Leader Charles E. Schumer (D-N.Y.) tweeted after the announcement, “I will not stop fighting to protect the Arctic National Wildlife Refuge and stop the Trump admin’s plan for drilling.”"
• (uncountable, informal) The administrative or managerial body of a company or other organization.
  "Barren dirt plots behind knee-high metal fences indicated admin must have cut the flower budget."
• (countable, informal) An administrator (one who administers affairs).
  "Georgia’s election administrators are fighting bizarre conspiracy theories, ballooning costs and coronavirus-related staffing problems as they prepare for the state’s contentious, nationally watched Senate runoffs next week."

verb

• (transitive, computing, informal) To serve as an administrator for or of.