What does "measuring worm" mean?

The larva of a moth of the family Geometridae.

What is a synonym for "measuring worm"?

Common synonyms include: cankerworm, inchworm, looper, tapeworm, worm.

noun

noun ·Rare ·Advanced level

Noun

1
The larva of a moth of the family Geometridae.
2
small hairless caterpillar having legs on only its front and rear segments; mostly larvae of moths of the family Geometridae wordnet

So called because their gradual movement seems to be measuring the ground; compare inchworm.