interpolate
to insert or estimate between known points
Roots
- inter-: between or among
- poli / polire: smooth, polish, or refine
Other words with the poli / polire root
- extrapolate: to infer beyond the known data
- polish: to make smooth or bright by rubbing
- polite: showing refined or respectful manners
Interpolate puts something between: a line between known points or material inserted into a text.
The chart interpolated the missing value between two measured points.
Inter- gives between. The older smooth/polish root is tucked inside the -polate ending, but the useful modern contrast is simple: interpolate works between known points; extrapolate moves beyond them.