pentynyl
/ˈpɛntɪnʌɪl/ /ˈpɛntɪnɪl/(also pentinyl) Chemistry. Now rare
noun
An unsaturated hydrocarbon radical with the formula —C5H7; (now) specifically one containing a carbon–carbon triple bond. Usually as a formative element in chemical names.
Origin
Late 19th century; earliest use found in Henry Forster Morley (b. 1855). From pentyne + -yl.