- One who calls upon (a person, especially a god) for help, assistance or guidance.
- An invoker of God's mercy
- One who appeals for validation to a (notably cited) authority.
- One who conjures up spirits with incantations.
- Someone who induces as an inevitable consequence.
- One who solicits, petitions for, appeals to a favorable attitude.
- (computing) That which causes a program or subroutine to execute.
invoke + -er