'selection-wise' is a compound: 'selection' originates from Latin, specifically the word 'selectio', where 'se-' meant 'apart' and 'legere' (from Latin 'legere') meant 'to choose'; the suffix '-wise' originates from Old English 'wīs', meaning 'manner'.

'selection' came into English via Old French and Middle English from Latin 'selectio'; '-wise' is an Old English-derived suffix (from 'wīs') used to form adverbs/adjectives indicating manner or relation; the modern compound 'selection-wise' arose by combining these elements in modern English.

Individually, 'selection' meant 'the act of choosing' and '-wise' meant 'in the manner of'; combined, the compound's meaning stabilized as 'with regard to selection' (a topical/relational marker) and is used informally to indicate perspective or aspect.