Blimp
wiktionary
Origin not entirely certain. However, most historians believe that it is onomatopoeia for the sound a blimp makes when thumped. Although there is some disagreement among historians, credit for coining the term is usually given to Lt. A.D. Conningham of the British Royal Navy in 1915.
There is an often repeated, but false, alternative explanation for the term. The erroneous story is that at some time in the early 20th century, the United States military had two classes for airships: Type A-rigid and Type B-limp, hence “blimp”. In fact, A. D. Topping reports on the “Etymology of ‘Blimp’”, in the AAHS Journal, Winter 1963, that:
etymonline
blimp (n.)
"non-rigid airship," 1916, of obscure origin, with many claimants (even J.R.R. Tolkien had a guess at it). "One of the weird coinages of the airmen" [Weekley]. Common theory (which dates to 1919) is that it is from designers' prototype nickname Type B-limp, in the sense of "without internal framework," as opposed to Type A-rigid; thus see limp (adj.), but references are wanting. There apparently was a type b in the U.S. military's development program for airships in World War I.