'school-supporting' is a Modern English compound formed from 'school' + 'supporting'. 'school' comes from Old English 'scolu' (via Latin 'schola'), meaning 'a place of learning'; 'supporting' derives from Latin 'supportare' (via Old French and Middle English), where the elements conveyed carrying or assisting.

'school' came into English from Latin 'schola' through Old English 'scolu'; 'support' evolved from Latin 'supportare' to Old French and Middle English forms such as 'souten'/'supporten', eventually yielding Modern English 'support' and the present participle 'supporting'. The compound arose by productive combination of noun + present participle in Modern English.

Originally, roots of 'support' had the sense 'to carry from below' (Latin: to carry under), but over time the sense broadened to 'to assist or provide help'; thus 'supporting' now commonly means 'giving assistance', and 'school-supporting' means 'providing assistance to schools'.