por'-shun: As far as a distinction between these words is possible in English, it lies in the fact that a "portion" is a "part" about whose destiny something is implied (Ps 142:5, etc.). The Hebrew has no two synonyms similarly related, and in consequence the use of the words in English Versions of the Bible is settled either by rather arbitrary considerations (menah, is always "portion" in the Revised Version (British and American), but is "part" in the King James Version, Ex 29:26; Le 7:33; 8:29) or by the context, irrespective of the Hebrew word used. So "part" and "portion" both represent dabhar, 1Ki 6:38; Ne 12:47; peh, Zec 13:8; De 21:17; chebhel, Jos 17:5 (Revised Version); Eze 47:13; meros, Lu 11:36; 12:46. And in the vast majority of cases in the Old Testament both words represent simply some derivative of chalaq, normally the noun cheleq.
Burton Scott Easton