noun
elongation
ee-lawng-GAY-shun/ˌiːlɔːŋˈɡeɪʃn/
The process or result of becoming or making something longer.
The three stages show progressive elongation of the soft clay strip.

Etymology
“Out” and “long” underlie a Latin verb meaning to remove to a distance. Its action noun also conveyed extension or spreading, the connection to the act or state of becoming longer.
In context
it's usually elongated fingers that's talking about the physique of that child longer elongation of bones
More examples
- Heat causes a slight elongation of the metal rod.
- Rapid stem elongation helps the seedlings reach the light.
- The artist's elongation of the figures makes them look unusually tall.
Forms
elongation · elongations
elongate verb — To make longer or become longer.
Similar words
- lengthening
- The everyday term for making or becoming longer.
- extension
- Often involves adding length rather than stretching existing material.
- stretching
- Specifically suggests pulling something longer through tension or force.