A flight feather that appears between the primaries and secondaries on some birds.
"The ornithologist carefully examined the bird's wing to identify whether an axial feather was present between the primary and secondary groups."
of or relating to or resembling an axis of rotation
"The spinning top maintained its stability because its mass was distributed symmetrically along its axial line, allowing it to rotate smoothly without wobbling."
situated on or along or in the direction of an axis
"The engine's crankshaft is positioned axially within the cylinder block to ensure smooth rotation around its central line."
Relating to, resembling, or situated on an axis
"The axial tilt of Earth determines how sunlight reaches different parts of the planet throughout the year."