1.
aorta
The main artery of the body, carrying oxygenated blood from the heart to the rest of the circulatory system.
2.
main artery, lifeline, vital route
Used figuratively for a crucial transportation route, supply line, or channel that sustains a region or system.
Common patterns
大 (large) + 動脈 (artery). The anatomical term refers to the body's largest artery.
Usage
The figurative sense (sense 2) is very common in news and business contexts, where major highways, railways, and shipping routes are described as 大動脈 of the economy or transportation system.