portionist

from The Century Dictionary.

• noun Eccles., same as portioner, 3.
• noun In Merton College, Oxford, same as postmaster, 3.

from the GNU version of the Collaborative International Dictionary of English.

• noun A scholar at Merton College, Oxford, who has a certain academical allowance or portion; -- corrupted into postmaster.
• noun (Eccl.) One of the incumbents of a benefice which has two or more rectors or vicars.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A scholar at Merton College, Oxford, England, who has a certain academical allowance or portion.
• noun One of the incumbents of a benefice that has two or more rectors or vicars.