Poecilonymy

Stated in technical linguistic terms, in this treatise poecilonymy is avoided; e. g., instead of taenia hippocampi in one place, corpus fimbriatum in another, and fimbria in a third, the last is consistently employed and the others given as synonyms.

Source: wiktionary

There are also too many relapses into poecilonymy; for example, on p. 758 occur appendix vermiformis, appendix, and rermiform appendix, whereas on p. 160 had already been introduced, without explanation, the very convenient contraction of the third term into vermix.

Source: wiktionary

Based on distinctions by Philo (Alleg. Interp. 3.70 §§196–97), δόσις sometimes is seen as the act of giving and δώρημα as the thing given, but James may simply be using poecilonymy (a piling up of synonyms) to emphasize God's generosity, or he may be quoting an extant “saying” or expressing himself poetically.

Source: wiktionary