Is not the suffix "heit" a form of the word "hot" or related to it? Or word a German, who did not know it was someone's last name, think it was derived from a word describing temperature? I could see the scientist having a different name than Fahrenheit but because of usage, the original name was corrupted to this?

Technology being named after a person is extremely common (probably the most common way units of measure in particular are coined) and also whimsical, at least temporarily -- there was a bio of Bell starring the American actor Don Ameche and for a while, people would say things like "the Ameche is ringing" even though the descriptive word "telephone" seems fine to me.

Is "heit" an ending found in other German names, making it less likely that people decided to change the original name (of the inventor and the measurement and then, retroactively of his ancestors)? If it is rare, then I think it could have been changed and 350 years ago is a long time -- even my own family we are unsure of original names before immigrating to USA just about a century ago. I can think of exactly no way to find out anything at all, including names, about any ancestor much further than 1850. The famous situation of some random bureaucrat at the immigration point choosing a name, not to mention that some were assigned names in the "Old Country" by another set of bureaucrats during the 1800s plus two world wars etc. sure have a way of obscuring one's past.

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    What, if any, research did you do on your question and about Daniel Fahrenheit's life circumstances? (en.wikipedia.org/wiki/Daniel_Gabriel_Fahrenheit) Do you have reason to surmise that his name was not "Fahrenheit" during his lifetime? Historians, biographers etc. follow the "paper trail": birth and marriage records, (in this case also) letters and publications; and establish facts, leaving little room for guesswork. Hint: his 1724 publication on temperature (London, Royal Society) is credited to "D. G. Fahrenheit".
    – marquinho
    Commented Dec 10, 2022 at 8:50
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    European paper trails of family heritage date back quite some centuries and are relatively accurate due to church traditions in marriage and birth records. It is very unlikely the family name was ever changed significantly.
    – tofro
    Commented Dec 10, 2022 at 8:54
  • I looked it up in wikipedia and on this very site and there seems to be some question about the origin of the name. I am asking native German speakers their impression of the name -- I have 3 plus years of German and my impression initially was that the word did have to do with heat. The question about other names containing heit as suffix -- I have read a lot of German and I can't recall any name like it. Heisenberg comes to mind as one that reminds me of this -- I would think, naively, oh Hot Mountain.
    – releseabe
    Commented Dec 10, 2022 at 8:56
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    The assumption that famous people tend to live up to their last names' original meaning sounds somewhat ridiculous to me - A recent U.S. president comes to mind who didn't quite manage to....
    – tofro
    Commented Dec 10, 2022 at 8:58
  • @marquinho: I did see that - again, I was wrong fixated on what looked like a suffix suggestive of "heat" -- I have studied many, many languages and can understand a enough to get by as a tourist in probably close to a dozen. But at my age I am resigned to really only speaking one, English, and asking dumb questions about the rest.
    – releseabe
    Commented Dec 10, 2022 at 9:04

2 Answers 2


Even if it might sound similar, -heit has absolutely nothing to do with "heat". -heit is a German suffix modifying nouns as to mean as much as "the wholeness of it" - like in

Mensch - man, Menschheit - mankind

or modifying adjectives to nouns denoting the property like in

stur - stubborn, Sturheit - stubbornness.

(just like the English suffixes -ness or -hood).

While the name Fahrenheit isn't really a word in German, if you absolutely want a translation, it would end up somewhat like "drivingness" or "travellingness".

There are quite a number of alternative possible interpretations of the name like "-heit" stemming from "Heide" (heathen) which might be more plausible (originally, names were most often derived from places or occupations, and rather not from abstracts), but the definite answer might be long lost.

  • There you go, the answer I was looking for from a native speaker. Thanks.
    – releseabe
    Commented Dec 10, 2022 at 8:57
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    German cognates of "hot" and "heat" are their exact translations: "heiß" and "Hitze".
    – RHa
    Commented Dec 10, 2022 at 9:13

Is not the suffix "heit" a form of the word "hot" or related to it?

No. -heit and -keit are cognates to English -hood.

  • Freiheit — “free-hood” — freedom
  • Gereiztheit — “riled-hood” — huffiness
  • Langsamkeit — “lag-hood” — slowness
  • Heiterkeit — “cheer-hood” — cheerfulness

As you can see, we use it when English would prefer -ness or -dom.

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    English -ness and -dom have German cognates too: -nis and -tum. Examples: Finsternis -- darkness, Reichtum -. wealth, riichness, literally "richdom".
    – RHa
    Commented Dec 10, 2022 at 9:09
  • Those suffixes are even more mixed up than prepositions.
    – Janka
    Commented Dec 10, 2022 at 10:49

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