from The American Heritage® Dictionary of the English Language, 4th Edition
- n. The negative univalent radical HCO, characteristic of aldehydes.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The univalent radical -CHO, derived from formaldehyde, that is characteristic of aldehydes
from the GNU version of the Collaborative International Dictionary of English
- n. A univalent radical, H.C:O, regarded as the essential residue of formic acid and aldehyde.
- n. Formerly, the radical methyl, CH3.
from The Century Dictionary and Cyclopedia
- n. A hypothetical univalent radical (CHO), of which formic acid may be regarded as the hydrate.
form(ic acid) + -yl.(American Heritage® Dictionary of the English Language, Fourth Edition)