diff --git a/lisp/calc/calc-units.el b/lisp/calc/calc-units.el
index 42156b94606..cc1f5085a7c 100644
--- a/lisp/calc/calc-units.el
+++ b/lisp/calc/calc-units.el
@@ -319,28 +319,28 @@ that the combined units table will be rebuilt.")
 (defvar math-unit-prefixes
   '( ( ?Q  (^ 10 30)  "quetta"  )
      ( ?R  (^ 10 27)  "ronna"  )
-     ( ?Y  (^ 10 24)  "Yotta"  )
-     ( ?Z  (^ 10 21)  "Zetta"  )
-     ( ?E  (^ 10 18)  "Exa"    )
-     ( ?P  (^ 10 15)  "Peta"   )
-     ( ?T  (^ 10 12)  "Tera"   )
-     ( ?G  (^ 10 9)   "Giga"   )
-     ( ?M  (^ 10 6)   "Mega"   )
-     ( ?k  (^ 10 3)   "Kilo"   )
-     ( ?K  (^ 10 3)   "Kilo"   )
-     ( ?h  (^ 10 2)   "Hecto"  )
-     ( ?H  (^ 10 2)   "Hecto"  )
-     ( ?D  (^ 10 1)   "Deka"   )
+     ( ?Y  (^ 10 24)  "yotta"  )
+     ( ?Z  (^ 10 21)  "zetta"  )
+     ( ?E  (^ 10 18)  "exa"    )
+     ( ?P  (^ 10 15)  "peta"   )
+     ( ?T  (^ 10 12)  "tera"   )
+     ( ?G  (^ 10 9)   "giga"   )
+     ( ?M  (^ 10 6)   "mega"   )
+     ( ?k  (^ 10 3)   "kilo"   )
+     ( ?K  (^ 10 3)   "kilo"   )
+     ( ?h  (^ 10 2)   "hecto"  )
+     ( ?H  (^ 10 2)   "hecto"  )
+     ( ?D  (^ 10 1)   "deka"   )
      ( 0   (^ 10 0)    nil     )
-     ( ?d  (^ 10 -1)  "Deci"   )
-     ( ?c  (^ 10 -2)  "Centi"  )
-     ( ?m  (^ 10 -3)  "Milli"  )
-     ( ?u  (^ 10 -6)  "Micro"  )
-     ( ?μ  (^ 10 -6)  "Micro"  )
-     ( ?n  (^ 10 -9)  "Nano"   )
-     ( ?p  (^ 10 -12) "Pico"   )
-     ( ?f  (^ 10 -15) "Femto"  )
-     ( ?a  (^ 10 -18) "Atto"   )
+     ( ?d  (^ 10 -1)  "deci"   )
+     ( ?c  (^ 10 -2)  "centi"  )
+     ( ?m  (^ 10 -3)  "milli"  )
+     ( ?u  (^ 10 -6)  "micro"  )
+     ( ?μ  (^ 10 -6)  "micro"  )
+     ( ?n  (^ 10 -9)  "nano"   )
+     ( ?p  (^ 10 -12) "pico"   )
+     ( ?f  (^ 10 -15) "femto"  )
+     ( ?a  (^ 10 -18) "atto"   )
      ( ?z  (^ 10 -21) "zepto"  )
      ( ?y  (^ 10 -24) "yocto"  )
      ( ?r  (^ 10 -27) "ronto"  )