This is the definition of action only from Pokernews.com:
In many card rooms, with respect to an all-in bet, only a full bet is considered a legitimate wager, in terms of whether this constitutes a raise that can be re-raised. Anything less than a full bet is considered to be action only, that is, other players can call such a bet but not raise it. For example, Chloe bets $10. Henry calls. John goes all in for $14. When the bet gets back to Chloe, she is permitted only to call the extra $4; the same goes for John.
What I'm confused about is why it's called action only? Because according to the glossaries I've looked up, action means the betting within a poker hand and if I'm correct, this consists of a bet, a call, and a raise; but if I'm incorrect and that action is only limited to a bet, this still does not make sense to me considering the example given indicates that one is only permitted to call, so why call action only, why not call only? Am I missing something?