'axis-aligned' is a compound formed from 'axis' (from Latin 'axis', meaning 'axle' or 'axis') and 'aligned' (past participle of 'align', from Old French 'aligner'/'aleigner' based on Latin elements meaning 'to make a line').

'axis' entered English from Latin 'axis' via Middle English with the sense of 'axle' or 'line'; 'align' came into English from Old French 'aligner' (from a- 'to' + ligne 'line'), giving 'aligned' as the past participle. The compound 'axis-aligned' arose in technical usage (geometry, computing) by combining the two to describe objects oriented with respect to coordinate axes.

Individually, 'axis' originally referred to an axle or central line and 'align' meant 'to bring into line'; together, the compound evolved in modern technical contexts to mean 'oriented parallel to coordinate axes' (a more specific, domain-focused meaning).