A state with a thousand chariots is the classical byword for a great power.
Tips
history
In pre-Qin texts, one 乘 was a four-horse war-chariot, the standard unit for measuring military power: a 千乘之国 ("thousand-chariot state") was a major kingdom, and a 万乘 state referred to the Zhou royal house. By extension 乘 also came to mean 'four' as a number, and later 'historical record' - a chariot-load of events worth chronicling.
register
The shèng reading is purely classical/literary and survives almost only in fixed compounds: Buddhist 大乘 (Mahayana), 小乘 (Hinayana), the chengyu-style 千乘之国, and the bookish 史乘. Modern colloquial speech uses chéng for everything else.
Components
ideograph
乘shèng
to ride; to multiply; vehicle
Single fused unit of ten interleaved strokes - the modern shape overlays cursive residues onto a 禾-like body so historical components no longer separate cleanly. Best learned as the silhouette behind 乘车, 乘客, and 乘法. Filed under Kangxi #4 丿 by tradition, with no visible radical-element in the modern form.
Filed under radical 丿 (piě, #4) by convention. 丿 is not a separate component in 乘, so no strokes are highlighted.
