To call to mind (something) for some purpose.
To appeal for validation to a (notably cited) authority.
To cause (a program or subroutine) to execute.
To solicit, petition for, appeal to a favorable attitude.
To conjure up with incantations.
To bring about as an inevitable consequence.
To call upon (a person, a god) for help, assistance or guidance.
To ask (somebody) to do something.
To ask for (something).
A message sent over a network to a server.
Act of requesting (with the adposition at in the presence of possessives, and on in their absence).
Condition of being sought after.
A formal message requesting something.