pentyne
/ˈpɛntʌɪn/(also pentine) Chemistry
noun
Originally: any of a number of unsaturated hydrocarbons with the formula C5H8. Now specifically: an alkyne with this formula, especially (also 1- pentyne) the unbranched isomer CH≡CCH2CH2CH3.
Origin
Late 19th century; earliest use found in Henry Watts (1815–1884), chemist. From penta- + -yne.