|sinə̇|strȯ(ə)rs, sə̇ˈniˌs- adjective
also sin·is·tror·sal |sinə̇|strȯrsəl
Etymology: sinistrorse from New Latin sinistrorsus, from Latin sinistrorsum, sinistrorsus toward the left side, from sinistr-, sinister left, on the left side + versus, past participle of vertere to turn; sinistrorsal from New Latin sinistrors us + English -al — more at worth
1. of a plant : twining spirally upward around an axis from right to left:
a. : twining counterclockwise when the observer's point of view is within or above the spiral
b. : twining clockwise when the observer's point of view is outside the spiral — compare dextrorse
2. : sinistral c
• sinis·trorse·ly -slē also sinis·tror·sal·ly -səlē adverb