"Ready to fire" and "enabled" seem to be the terms of art used for transitions in Petri nets.

See http://www.project-open.org/product/modules/workflow/petri-n...
"It's important to differentiate between the time a transition is enabled (meaning it's ***ready to fire***) and the time it actually fires. A transition is enabled when there is at least one token in each of its input places. Firing the transition is the act of actually moving the tokens."

The glossary quoted below contains the following entries:
token = Marke
Basic element of a Petri net's marking. The ***readiness to fire*** of a transition requires that the transition's input places contain sufficient tokens.

enabled = schaltbereit
A transition in a petri net is enabled (ready to fire), if it meets two requirements:

(1) Each input place of the transition contains as many tokens as the arc weight specifies.
(2) Each output place of the transition can still accept as many tokens as the arc weight specifies.