shào is the bound morpheme for 'young' in compounds: 少年 (youth, teenager), 少女 (young girl), 少男 (young man), 老少 (old and young). It rarely stands alone — almost always inside a compound.
culture
shào also marks 'junior' military and household ranks: 少将 (major general), 少校 (major), 少尉 (second lieutenant), 少爷 (young master of the house). The thread: junior in age or rank — the next generation below the senior tier.
The 'small' base. For the shào reading the semantic link is 'small in years' — a young person is literally a 'little one'. Same indexing radical as the shǎo reading; the meaning split is a tonal one, not a structural one.
The fourth stroke that differentiates 少 from 小. Historically the shǎo ('few') and shào ('young') readings share one graph because both senses point at something diminished or not-yet-grown; the tonal split fossilised the distinction over time.
