输送
shū sòng · HSK 7
to transport
🚚 输 transport + 送 deliver = to convey goods along a route
输 carries the sense of transporting or piping something along; 送 means to send or deliver. Together 输送 is the steady conveying of goods, fuel, or people from one point to another, like a supply line.
输 — cart 車 + 兪 (phonetic)
输 is a phono-semantic compound. The radical 車 (cart/vehicle) gives the meaning, originally referring to transporting goods by cart. The component 兪 supplies the sound. From 'transport' it extended to 'send/deliver', then by metaphor to 'lose' (as in handing over stakes in a game).
送 — 辶 (walk) + 关 (simplified from 灷, fire/torch)
Originally depicted hands holding a torch to escort someone on a journey, combined with the 'walk' radical 辶. The right side 关 is a simplification of an older form showing fire being carried. The core meaning evolved from 'escort/see off' to the broader sense of 'send' or 'give as a gift.'