I have found the distinction between statistically significant and physically significant is often useful when communicating results to non-statisticians. The phrases clinically significant or practically significant may be preferred in some fields (thanks @Jelsema). You are describing a situation where the effect may be statistically significant, but physically insignificant.
As an aside, there is actually a push right now to stop (or limit) using the phrase "statistically significant" altogether. Some relevant reading:
Moving to a World Beyond "p < 0.05"
The Difference Between "Significant" and "Not Significant" is Not Itself Statistically Significant
Scientists rise up against statistical significance
Wasserstein, Ronald L., Allen L. Schirm, and Nicole A. Lazar. "Moving to a world beyond “p< 0.05”." (2019): 1-19.
Gelman, Andrew, and Hal Stern. "The difference between “significant” and “not significant” is not itself statistically significant." The American Statistician 60.4 (2006): 328-331.
Amrhein, Valentin, Sander Greenland, and Blake McShane. "Scientists rise up against statistical significance." (2019): 305-307.