1936, coined from lobe (in the brain sense) + medical suffix -tomy "a cutting." Figurative use is attested from 1953. Lobectomy (attested from 1911) was in use earlier in reference to lobes of other organs (lungs, liver).
Now I guess I'll have to tell 'em
That I got no cerebellum
[Ramones, "Teenage Lobotomy," 1977]
Meaning "thread-like structure in animal bodies" is from c. 1600 (in plants, 1660s); hence figurative use in reference to force or toughness (1630s). As "textile material," 1827. Fiberboard is from 1897; Fiberglas is attested from 1937, U.S. registered trademark name; in generic use, with lower-case f- and double -s, by 1941. Fiber optics is from 1956.
order of lobe-finned fishes, 1850, from Modern Latin Coelacanthus (genus name, 1839, Agassiz), from Greek koilos "hollow" (from PIE root *keue- "to swell," also "vault, hole") + akantha "spine" (from PIE root *ak- "be sharp, rise (out) to a point, pierce"). So called from the hollow fin rays supporting the tail in fossil remains.
Thought to have gone extinct 66 million years ago until a living one was fished up off the east coast of South Africa Dec. 22, 1938. The specimen was noticed by museum curator Marjorie Courtney-Latimer, who wrote a description of it to South African ichthyologist J.L.B. Smith.
I stared and stared, at first in puzzlement. I did not know any fish of our own, or indeed of any seas like that; it looked more like a lizard. And then a bomb seemed to burst in my brain, and beyond that sketch and the paper of the letter, I was looking at a series of fishy creatures that flashed up as on a screen, fishes no longer here, fishes that had lived in dim past ages gone, and of which only fragmentary remains in rock are known. [J.L.B. Smith, "Old Fourlegs: The Story of the Coelacanth," 1956]