'isolecithality' originates from Greek-derived scientific elements: the prefix 'iso-' from Greek 'isos' and the root from Greek 'lekithos', where 'isos' meant 'equal' and 'lekithos' meant 'egg yolk', combined with the English noun-forming suffix '-ity'.

'isolecithality' developed from the adjective 'isolecithal' (formed in modern scientific/biological usage from Greek elements) with the addition of the nominalizing suffix '-ity' to denote the state or quality, producing the noun 'isolecithality' in contemporary embryological terminology.

Initially it conveyed the idea 'having equal or uniformly distributed yolk', and it has come to mean specifically 'the condition or quality of eggs with yolk evenly distributed', used as a technical term in embryology and zoology.