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Had to ask this in electronics, would like to hear this from people who have been involved. I am not a native English speaker, and I couldn't find a definitive answer online: there are too many variants that looked odd to me. There probably should be a way engineers pronounce this word?

Elliot Alderson
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Jimmy Falcon
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  • I can only answer based on the pronunciation in the US and what I've heard from other areas, which is kill-oh-ohm or kill-ah-ohms. (Maybe keel-o in some places.) But nobody uses term regularly, we just abbreviate it to "K". So "go grab me a 4.75K resistor' would be the most common usage., Sometimes K-ohm as well. Almost never kiloohms. – John D May 21 '22 at 10:24
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    "Kilo-Ohm" is a international unit. I strongly assume, its pronunciation differs from locale to locale. So possibly migrate to the respective language stack exchange ?? – tobalt May 21 '22 at 11:44
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    As a fellow non-English speaker, where did you see this? It's the first time I've seen/heard it without the full "kiloohm" – pipe May 21 '22 at 15:08
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    wouldn't you pronounce it in similar way as kilogram and kilometer? – jsotola May 21 '22 at 18:11
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    My first question is if "kilohm" is even a word. But of course, that, too, might be regional. – ilkkachu May 22 '22 at 08:51
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    BTW, note that SI standard mandates the spelling of the prefixed units, but not the pronunciation. The correct spelling is "kiloohm", with two "o". See latest SI brochure. – LorenzoDonati4Ukraine-OnStrike May 22 '22 at 09:25
  • @LorenzoDonatisupportUkraine No, the correct spelling is with a single o: kilohm. – Elliot Alderson May 22 '22 at 22:37
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    @ElliotAlderson Sorry, I don't agree wrt SI. See the SI brochure I linked to. At p.143 (p.29 of the PDF): Similarly prefix names are also inseparable from the unit names to which they are attached. Thus, for example, millimetre, micropascal and meganewton are single words. And also at p.148: When the name of a unit is combined with the name of a multiple or sub-multiple prefix, no space or hyphen is used between the prefix name and the unit name. The combination of prefix name and unit name is a single word (see chapter 3). – LorenzoDonati4Ukraine-OnStrike May 23 '22 at 09:16
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    @ElliotAlderson According to those paragraph the prefix "kilo" and the unit name "ohm" are joined to the single word "kiloohm". SI has no provisions to simplify spelling into "kilohm". BTW, Note that the normative SI text is the French one. The English translation I linked to is provided by BIPM for convenience. If NIST guidelines are different from SI rules, that's another matter. – LorenzoDonati4Ukraine-OnStrike May 23 '22 at 09:19
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    I don't think this is opinion-based. The pronunciation of terms is part of technical communication, which is completely on-topic, especially in multcultural environment (what if two engineers from different country spell a word differently and the communication fails during a critical operation?). The subject may be regional, country- or language-specific, but it's not opinion based (common practices are not opinions). Voting to reopen. – LorenzoDonati4Ukraine-OnStrike May 23 '22 at 09:24

4 Answers4

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9.3 Spelling unit names with prefixes

When the name of a unit containing a prefix is spelled out, no space or hyphen is used between the prefix and unit name (see Sec. 6.2.3).

Examples: milligram but not: milli-gram kilopascal but not: kilo-pascal.

Reference [6] points out that there are three cases in which the final vowel of an SI prefix is commonly omitted: megohm (not megaohm), kilohm (not kiloohm), and hectare (not hectoare). In all other cases in which the unit name begins with a vowel, both the final vowel of the prefix and the vowel of the unit name are retained and both are pronounced.

Source: Guide for the Use of the International System of Units (SI).

Transistor
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  • (+1) Good reference. I was commenting on this on the question when I spotted your answer. As for reference [6]: IDK if that note is normative. IIRC SI mandates that the spelling is unaltered, so "kiloohm" spelling cannot be simplified as "kilohm". As for the OP the problem of how that term is pronounced remains. – LorenzoDonati4Ukraine-OnStrike May 22 '22 at 08:01
  • SI latest brochure: https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf – LorenzoDonati4Ukraine-OnStrike May 22 '22 at 09:17
  • Link to the latest version of the NIST Guide, at chapter 9: https://www.nist.gov/pml/special-publication-811/nist-guide-si-chapter-9-rules-and-style-conventions-spelling-unit-names – Massimo Ortolano May 22 '22 at 14:55
  • All hail the great uniter. +1. (and that wasn't even the way I've heard the most) – Mister Mystère May 22 '22 at 21:27
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I'm a retired US electrical engineer who spent his time in defense electronics research at a fairly well-known defense laboratory associated with MIT. I've lived all my life in New England.

I've never heard anything other than KIL-om. Short i, long o. From your point of view, as if it is "kill ohm", with the accent on "kill". The accent is not strong, and is sometimes absent. Likewise one million ohms is "MEG ohm", with the e being pronounced as if it is a long a, as is done with the words "peg" and "leg".

Informally, among other electronicers, a kilohm would simply be called a "K". As in "ten k". For larger resistances, just "meg".

EDIT. As has been mentioned in comment, the Brits apparently pronounce both o's. So you should consider tailoring your pronunciation to whichever side of the ocean you expect to talk to.

WhatRoughBeast
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    Over 10 years in electronics and I've never heard the first "o" being dropped before. Where I'm from (UK) you pronounce both o's seperately "kilo-ohm" – ChrisD91 May 21 '22 at 12:45
  • @Jimmy Falcon - I appreciate the upvote, but generally it's a good idea to hold off for 24 hours or so. No matter how perfect an answer may seem (and all of my answers are, of course, perfect) there is always the chance that someone may come along with a better one. Or even, God forbid, evidence that the answer is wrong. – WhatRoughBeast May 21 '22 at 12:47
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    @ChrisD91 - I'm not all that surprised. That's why I specified my nationality/geographic area. Television has been a great leveler of accents, but it can't level what isn't said. And electronic component values just don't seem to get discussed much on popular shows. I wonder why that is? – WhatRoughBeast May 21 '22 at 12:52
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    I'm not sure of the relevance of your MIT-associated defense lab experience except to brag or to prop up the authority of the answer - which does not fit with my experience either in the U.S. or in English-speaking Europe. I hear "kill-oh" (though as others commented, simply "kay" is more common). -1 – TypeIA May 21 '22 at 13:51
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    @ChrisD91 I'm also in the UK, and don't recall anyone ever saying "kilo-ohm". Of course, most of the time it's just "kay", as per TypeIA's comment. – Simon B May 21 '22 at 17:18
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    "kilo-ohm" is also in the US - that's the way I've said it for over 40 years. There are two "o"s... Western US. – Steve May 21 '22 at 20:30
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    UK engineer here, it's 'kill' 'ohm', or 'k', never heard anybody say 'kilo' 'ohm', however correct it might be thought to be. – Neil_UK May 21 '22 at 20:54
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    @Simon B I think the only thing that everybody agrees on is that most of the time it's just "kay" – ChrisD91 May 22 '22 at 07:30
  • @Neil_UK would you also say "kill" "gram" when discussing kilograms? I'm honestly surprised everyone is saying something different. – ChrisD91 May 22 '22 at 07:34
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    @ChrisD91 Absolutely not, what a silly thing to say. Gram starts with a consonant, so saying the vowel at the end of kilo is completely natural. I must confess it's more of a 'killer' 'gram', than a 'kilo' 'gram', but people understand it. The French are much more upfront about these pronunciation issues, having a policy of altering the sound so that it's mellifluous rather than ugly. – Neil_UK May 22 '22 at 08:44
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    @TypeIA - I was simply giving my background. I included New England because I thought it might be important (and it apparently is, if the British comments are any indication. I included my professional background because I've no way to tell if, for instance, engineers or technicians in manufacturing use the same terminology. For all I knew, my pronunciation might be unique to the lab I worked for. So I thought I should be upfront about my background. – WhatRoughBeast May 22 '22 at 19:33
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    Lived in France, UK, and Canada now - I'm pretty sure I've always heard "kay" and "kilo-Ohm" even if the first 'o' gets chewed easily, but all the engineers I've come across who'd happily forget about the first 'o' altogether would just drop everything for 'kay'. Much like we say "keuro" for "thousands of euros" (at least in my former company, which is certainly just as known), and sometimes "kilo-euro" for 100% correctness but never "kileuro". Anything to save time as long there is no misunderstanding possible and that standards are respected on paper. – Mister Mystère May 22 '22 at 21:24
  • FWIW, in Italian most words are pronounced as they are written, and when that doesn't happen there are very strict pronunciation rules (dialects apart), so this variability of pronunciation of written words is typical of English, given the irregularities of its pronunciation rules (are there any that are strict?) and the fact it is spoken in so many countries all over the world (even as an L2 language). In Italian we pronounce it "kee-loh-ohm", with the two "o" distinctly separated. – LorenzoDonati4Ukraine-OnStrike May 23 '22 at 09:34
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So those who use resistors ask, as an example, for a 10-meg resistor as we all know the ohms bit.

Solar Mike
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The second syllable of kilo, when used in kilohm, is a schwa - an indistinct vowel sound - it's pronounced like 'uh'. So we say 'ki-luh-ome'.

The classic example is 'elephant' - this is pronounced 'eh-luh-funt'. Nobody says 'eh-le-fant'.

Chu
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