Green Onions
Green onions have a mild onion flavor and tender green tops. They cook quickly and can also be used fresh as a garnish.
Identity
Fast onion flavor
Add early for aroma or late for freshness.
The white and pale green parts can go into the pan with aromatics. Dark green tops are softer and work well near the end or as a garnish.
Wikimedia Commons
Reference image
Green Onions reference image.

Source: Wikimedia Commons
Used In Recipes
Substitutions
Acceptable
Chives -> Green Onions
¼ cup (⅔-ounce) chives or green onions (mostly green parts), cut into ¼-long pieces
The source lists this as an alternative in the same ingredient row.
Source: Best Stuffed Shells