infinitesimally
🇺🇸
/ˌɪnfɪnɪˈtesɪməli/
🇬🇧
/ˌɪnfɪnɪˈtesɪməli/
in a way that is extremely small or very close to zero
The surface of the mirror was polished to be infinitesimally smooth.
鏡の表面は微小なほど滑らかに磨かれました。