IPA: /dɪˈploʊməd/
KK: /dɪˈploʊməd/
Having completed a course of study and received a diploma, indicating a level of education or qualification.
She is a diplomaed professional in her field, having graduated with honors.
Diplomaed is derived from "diploma" (from Greek "diplōma", meaning folded paper or document) and the suffix "-ed" (indicating a state or condition). The term "diplomaed" refers to the state of having received a diploma or being certified by a diploma.
Think of a 'diploma' as a formal document that certifies achievement, and the '-ed' indicates that someone has achieved that status.