The designation “Mark 27 nuclear bomb” does not appear in widely recognized, authoritative reference works on nuclear weapons, such as official United States Department of Defense publications, declassified nuclear weapons histories, or major academic encyclopedias. Consequently, there is no verifiable, detailed encyclopedic entry for a weapon by this exact name.
The term can be interpreted within the broader context of United States military nomenclature. “Mark” (often abbreviated “Mk.”) has historically been used to label successive models of weapons and equipment, including conventional ordnance, torpedoes, and nuclear weapons. The numeral following “Mark” typically indicates the chronological order of development or adoption (e.g., Mark 17, Mark 24, Mark 28). If a “Mark 27” nuclear bomb had been conceived, it would presumably have been part of the United States’ Cold‑War era nuclear arsenal development program, fitting temporally between the known Mark 26 (a cancelled design) and Mark 28 (a deployed thermonuclear bomb). However, no reliable documentation confirms that such a device was designed, produced, or deployed.
Given the absence of corroborated sources, the term remains unverified in the public domain and is not regarded as an established concept within the historical record of nuclear weapons.
