bravely volunteer, counter for guns, inksticks, palanquins, rickshaws
挺 centers on the idea of standing out or extending forward: bravely volunteering oneself, or serving as a counter for long, protruding objects like guns, inksticks, palanquins, and rickshaws.
挺 combines 扌 (hand) with 廷, which likely contributes the sound and the idea of extending or straightening. The historical development of 廷 itself is complex, but the overall phono-semantic structure is clear.
A hand 扌 beside 廷, which looks like a person standing tall and extending forward. Picture a volunteer stepping forward with hand raised, or a long object being held out to count.
For チョウ, imagine a brave volunteer named Chou stepping forward with hand raised: Chou -> チョウ, and his hand extends to volunteer.
airborne (troops, operation, etc.)
offering oneself (for); volunteering (to do); coming forward; going ahead of others
women's volunteer corps; groups of young female workers organized on Japanese territory during WWII
to put (oneself) forward; to risk (one's life); to volunteer (bravely)
to put (oneself) forward; to risk (one's life); to volunteer (bravely)
caudex (of a plant)
military unit composed of personnel who have volunteered for dangerous assignments; volunteer corps
going ahead of the others; advancing ahead of the main force
advance unit sent ahead of the main force on a special mission
Special Air Service; SAS
airborne operation
paratrooper
airhead
airborne division
airborne brigade; parachute brigate
airborne troops; paratroops
drop zone
airborne troops; paratroops
paratroopers
Special Air Service; Special Air Service Regiment