ˈepəˌsōm noun
( -s )
Etymology: epi- + -some (III)
: a genetic determinant (as the DNA of some bacteriophages) that can replicate either autonomously in bacterial cytoplasm or as an integral part of their chromosomes — compare plasmid herein
• epi·som·al ¦epə¦sōməl adjective
• epi·som·al·ly adverb
• epi·so·mic -ōmik adjective