Right now I am writing a technical report, where I describe asymptotic(al) curves, expansions etc. My understanding after a bit of web browsing is that asymptotic and asymptotical are near-synonymous but the former is much more common (please correct me if I am wrong), so I will replace all instances of asymptotical by asymptotic.

Is there any general rule for those X vs. X-al situations? I can handle the most common cases (such as "Economic" vs. "economical") because I have seen them enough times, but I have not inferred a general rule, so I am at a loss when presented with an uncommon word (such as "asymptotic").

(I am not a native speaker.)

  • 1
    You have to be very careful with some words: historic is different from historical. (Just as is economic from economical.) If you don't know, look up the words in a dictionary. Commented Aug 12, 2019 at 22:18
  • @JasonBassford I agree in principle. However, historic vs historical returns thousands of relevant links in Google, whereas asymptotic vs asymptotical does not.
    – user357497
    Commented Aug 13, 2019 at 15:55
  • I'm not talking about Google. I'm talking about looking up the words in a dictionary. Unless Google leads you to an online dictionary, it's a terrible tool in general. Commented Aug 14, 2019 at 4:14
  • are gold/en and wood/en like mystic/al, classic/al, magic/al, comic/al?
    – BCLC
    Commented Sep 7, 2021 at 13:10

2 Answers 2


There are historical reasons behind the choice of the suffixes -ic - ical as explained here:


compound adjectival word-forming element, usually interchangeable with -ic but sometimes with specialized sense (such as historic/historical, politic/political), Middle English, from Late Latin -icalis, from Latin -icus + -alis (see -al (1)).

Probably it was needed because the forms in -ic often took on a noun sense (for example physic). Forms in -ical tend to be attested earlier in English than their twins in -ic.


  • 1
    So... no general rule. Well, that's English I guess.
    – user357497
    Commented Aug 13, 2019 at 15:56

I have been thinking about this a lot recently and i have decided that perhaps the general rule is:

a single element is -ic, a battle is historic, a light switch is electric, 2+2=4 is arithmetic, Gandalf is Fantastic, a money saving tip is economic, a piece of logic is well, logic.

A more complex thing made of many -ic elements is -ical. a War is historical, the wiring in a whole house is electrical, a system made up of many pieces of arithmetic is arithmetical, Lord of the Rings is Fantastical, living your life following money saving tips is economical, and carrying out a task using logic is logical.

  • Welcome to EL&U. Your reasoning does not hold up to scrutiny, but if you can identify a reputable reference that supports it, please edit the answer to include it. I strongly encurage you to take the site tour and review the help center for additional guidance.
    – choster
    Commented Aug 22, 2019 at 12:50

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