P5184600 (pĕn′tə-kwôrk′, -kwärk′)n. A hypothetical subatomic particle consisting of five quarks, of which either one or four are antiquarks.
pentaquark
(ˈpɛntəˌkwɑːk) n (Atomic Physics) physics a postulated subatomic particle consisting of four quarks and one antiquark, thought not to exist in actuality[C21]