Mid 19th century; earliest use found in National Preacher. From ancient Greek ἐπιστήμη knowledge, understanding, skill, scientific knowledge from ἐπιστάναι to know, understand + -μη, suffix forming nouns; the -η- of the second syllable of ἐπιστήμη is probably after nouns such as μνήμη memory, ϕήμη words, speech.