Elementary particle physics seemed to be "converging" at last
on a simple description in terms of a manageable number of
really elementary constituents intil around 1964, when
some rogues suggested that if there were 6 leptons (counting
the neutrinos) then there ought to be 6 quarks too, Nature being
endowed with frugality and æsthetics just like Mathematicians.
Actually the argument may have been more convincing than that,
but I didn't understand it. This might not have raised many
eyebrows except that in 1974 two huge groups of particle physicists
led by Burton Richter and Samuel Ting simultaneously
(or so close that no one could claim the other had stolen the idea)
discovered a new meson that was both very heavy (3100 MeV
)
and extremely stable (
s). [Well, for a
particle that heavy, 
s is a long time!]
This particle, which has the unique disadvantage of two names
- J and 
- because of the unusual circumstances of its
discovery and the enormous egos required for undertaking and
directing such huge experiments, was immediately recognized
to be the manifestation of a new kind of quark, the c quark,
which had yet another weird property conserved by strong interactions.
In an unsuccessful attempt to compensate for the callousness
with which useful words had been ripped off from the English
language in the past, the new property was named (groan)
"charm."
Now there is a whole new menagerie of charmed particles to complicate matters; and (skipping ahead to today) another of the predicted 6 quarks has been found as well. It is the b quark, and what the "b" stands for makes an interesting story.
The final(?) two quarks were originally posited to manifest two additional conserved properties called truth (t) and beauty (b). This, however, was too much even for the particle physics community. Whether we were finally exercising some retraint or had merely become embarrassed by newspaper headlines reading, "CERN physicists hunt for Naked Bottom," or "Still no Truth in Quark Hunts," shall never be known. It was, however, decided to retroactively change the names of the new quarks (and their corresponding properties) to "top" and "bottom" - which, you will note, have the same first letter as the old names, so that the old publications written by particle physicists who forbear to use the full names were still valid.
Now, personally, I think this was a mistake. No one is fooled by this attempt to pretend particle physicists are not crazy megalomaniacs, and now we have to try to remember the difference between up-down and top-bottom. Perhaps newly discovered particles should be submitted to a panel of English scholars for naming, but this would take some of the fun out of particle physics, and if it isn't fun then what is there to keep it going? Hmmm....