ˈbyüˌtīn noun
( -s )
Etymology: International Scientific Vocabulary but- + -yne, -ine
: either of two isomeric hydrocarbons C 4 H 6 of the acetylene series:
a. : an easily condensable gas CH≡CCH 2 CH 3 — called also 1-butyne, ethylacetylene
b. : a volatile liquid CH 3 C≡CCH 3 of strong odor — called also 2-butyne, dimethylacetylene