Bug Refers to a hardware or software fault in a computer. The common use of the term bug goes back to World War II, although its use in the context of electrical devices has been traced back to at least the 1890s. Related Terms 100 EPC, Article 2G, 2.5G, 2.75G, 3G, 4G, 5G 337, Section 3GPP 6-Sigma (6-σ)