Definition
A fuse holder fitted with a small visible indicator -- usually a colored button, flag, or light -- that pops out or illuminates when the fuse inside has blown. It allows a technician or pilot to identify a failed fuse by sight, without removing each fuse from its holder for testing.
Plain English
A fuse socket with a built-in 'flag' that shows you at a glance which fuse has blown, so you don't have to pull each one out to check it.
Context Anchor
Seen on aircraft electrical panels, fuse panels, and during electrical troubleshooting or maintenance.
Derivation
Indicating comes from the Latin indicare, to point out or show; the key addition here is that the holder itself reveals the blown state rather than requiring separate testing.
Why Pilots Care
Allows rapid identification of failed circuits during preflight or in-flight troubleshooting without removing and testing each fuse individually.
Analogy
Like a circuit breaker that visibly pops outward so you can see at a glance which one has tripped.
Intuition Check
Do not read “indicating” as a full test of the electrical system. It only gives a visible sign about the fuse in that holder.
Example Sentence 1
After the landing light failed, the pilot glanced at the fuse panel and saw the small white button standing proud on an indicating fuse holder, confirming which fuse had blown.
Example Sentence 2
During the preflight inspection the mechanic scanned the panel of indicating fuse holders to confirm all circuits were intact.