Often American code names are from lists. List 1 - name one, List 2 name two. They generally had the same first letters. For example when we did REFORGERs in the fall/winter, they each had a codename. 1987 - Certain Strike, 1988 Certain Challenge, 1989- Centurion Shield. List 1 was the code names for Europe (C - words) List two was for the US Based units (S - words for III Corps units).
Same with each spring when V Corps did it's major exercise it was always a C (Europe based) G (V Corps only) named exercise like "Caravan Guard" or "Certain Guardian".
Desert Shield, Desert Storm and Desert Saber were given those names because D - Middle East, S- Multinational Forces.
Then there are those that are just made up locally like "All-American Tiger".
Some folks just have no imagination.