All 4 Uses of

intervene
in
Tenth Grade Bleeds

And if Nelly hadn't intervened ....he could have killed her—w ould have killed her.†
Chpt 7.

intervened = got involved or came between

If he intervened he'd not only be late to class, but he'd also likely walk away from his heroism with several bruises.†
Chpt 8. *

After all, if Vlad hadn't intervened, Jasik wouldn't have suffered D'Ablo's wrath and he might still be alive right now.†
Chpt 25.

He was about to ask a question when Henry intervened with the same thing he was thinking.†
Chpt 25.

Definitions:

(1) (intervene as in: intervened in the war)
the process of getting involved to influence an outcome
The exact meaning of intervention can depend upon its context. For example:
- "intervention program for at-risk youth" -- a process of trying to influence the direction of someone's life
- "medical intervention" -- action taken to improve a medical outcome
- "military intervention" -- interference by a government in affairs of another government (in this case to interfere militarily)
- "had a family intervention" -- an organized meeting of family members to encourage someone (who is often surprised) to recognize and work at solving a problem such as substance abuse
(2) (intervene as in: in the intervening years)
something between two other things -- especially the passage of time between two events
(3) (meaning too rare to warrant focus)
meaning too rare to warrant focus:

Much more rarely, intervene can mean:
in various senses, including:
- to verbally interrupt -- as in "Not now!' she intervened."
- to be physically between -- as in: "You can't walk from one hill to the other because an impassable river intervenes."