pentadecylic

from The Century Dictionary.

• Containing fifteen atoms of carbon in the molecule.
• A crystalline acid, C₁₄H₂₉.COOH, of the fatty series, which is made synthetically. It melts at 51° C. and is commonly called quindecylic acid.

from the GNU version of the Collaborative International Dictionary of English.

• adjective (Chem.) Same as quindecylic.