'sporadically-distributed' originates from a combination of 'sporadically' and 'distributed'. 'Sporadically' ultimately traces to Greek 'sporadikos' (from 'sporas/sporá') meaning 'scattered (as seed)'; 'distributed' derives from Latin 'distribuere', where 'dis-' meant 'apart' and 'tribuere' meant 'to allot, assign'.

'Sporadic' entered English via Medieval Latin 'sporadicus' from Greek 'sporadikos', with the adverb 'sporadically' formed by the -ally suffix. 'Distribute' came from Latin 'distribuere' through Old French into Middle English; 'distributed' is the past participle used adjectivally. The modern compound 'sporadically distributed' arose in scientific and technical prose and is often hyphenated when used attributively.

Initially, the roots conveyed 'scattered' and 'to deal out/assign.' Together they evolved to denote something 'spread in scattered, irregular fashion' in modern descriptive and scientific usage.