'leptokurtosis' originates from Greek, specifically the prefix 'lepto-' from 'leptos' meaning 'thin' or 'slender' and the element 'kurtosis' ultimately from Greek 'kurtos' meaning 'curved' or 'arched', with the suffix '-osis' indicating a condition.

'leptokurtosis' was formed in modern statistical English by combining the Greek prefix 'lepto-' and the term 'kurtosis' (itself adopted into statistical vocabulary in the late 19th–20th century) and became the technical term for distributions with pronounced peaks and heavy tails.

Initially it combined senses of 'thin/pointed' (lepto-) and 'curvature' (kurtos) in a descriptive way; over time it evolved into the technical statistical meaning 'a distribution with a sharper peak and heavier tails than the normal distribution.'