from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Of, relating to, or designating the third row of flight feathers on the basal section of a bird's wing.
- n. A tertial feather.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Any flight feather attached to the humerus (upper arm) of a bird.
from the GNU version of the Collaborative International Dictionary of English
- Same as tertiary.
from The Century Dictionary and Cyclopedia
- Of the third rank or row among the flight-feathers of a bird's wing; tertiary, as a quill-feather.
- n. A tertiary flight-feather; one of the pennæ, or large feathers, of a bird's wing of the third set, which grow on the elbow or upper arm; one of the tertiaries.
Latin tertius, third; see tertiary + -al1.(American Heritage® Dictionary of the English Language, Fourth Edition)