'low-arched' is a compound formed from the English adjective 'low' and the past-participial adjective 'arched'. 'low' originates from Old English (e.g. 'hlāw') where it meant 'not high', and 'arch' traces back to Latin 'arcus' meaning 'bow' (via Old French/Old English), where the root referred to a curved shape.

'low-arched' developed as a modern English compound combining Old English 'low' (not high) and the adjective 'arched' (from Latin 'arcus' → Old French 'arc' / Middle English 'arch'), eventually becoming the descriptive compound 'low-arched' in contemporary usage.

Individually, 'low' originally meant 'not high' and 'arch' originally meant 'bow-like curve'; over time their compound use stabilized to mean 'having a less pronounced (lower) arch', especially of the foot.