Update: The word trended again on November 28, 2017 after reports of a second missile launched by North Korea.
Ballistic was among our top look ups on July 28th, 2017, following North Korea’s firing of a missile which is modified by this particular adjective.
North Korea has taken another step toward achieving its stated goal of being able to send a nuclear weapon to the U.S. mainland, apparently firing another ballistic missile late Friday.
—Anna Fifield, The Washington Post, 28 Jul. 2017
Ballistic comes from the Latin word ballista, which was the name for a military siege engine which would hurl missiles a considerable distance. (Despite the similarity between the initial parts of the words, this is not the same root that gave us the word ball.)
The word has been used to mean “of or belonging to the hurling of missiles” since at least 1764, but in the mid-20th century the term ballistic missile was coined to refer to a missile designed to fly in the high-arch trajectory of a true ballistic object. Ballistic missiles are self-guided and self-powered for most of their ascent, but become free-falling objects in descent. (Meanwhile a cruise missile is a guided missile that has a terrain-following radar system and that flies at moderate speed and low altitude.) The phrase go ballistic, meaning "to become very angry or excited," is found in informal speech and writing, often in contexts unrelated to military matters; it appears to date to the 1980s and probably has its origin in the idea of a missile in its free-fall, no longer guided by anything other than gravity.
