Meaning of INFINITESIMAL in English

INFINITESIMAL

in ‧ fin ‧ i ‧ tes ‧ i ‧ mal /ˌɪnfɪnəˈtesəm ə l◂, ˌɪnfɪnɪˈtesəm ə l◂/ BrE AmE adjective

[ Date: 1600-1700 ; Language: Modern Latin ; Origin: infinitesimus 'infinite in rank' , from Latin infinitus ]

extremely small SYN minuscule :

infinitesimal changes in temperature

—infinitesimally adverb :

infinitesimally small

Longman Dictionary of Contemporary English.      Longman - Словарь современного английского языка.