This is the complete sentence where I found it. It is from an online training about the Linux operating system.

e4defrag is part of the e2fsprogs package and should be on all modern Linux distributions, although it doesn’t come with RHEL 6 which is somewhat long in tooth.

What does which refer to? What is the meaning of the expression "somewhat long in the tooth," and where does it come from?

Cambridge International Dictionary of Idioms(1998) has this entry for the expression:

be long in the tooth humorous

to be too old | The older a horse is, the longer its teeth are | I'd have thought she was a bit long in the tooth to be starring as the romantic heroine.

This explanation suggests that the long teeth in the original expression belonged to horses—and not, say, beavers (or human beings). But it doesn't identify how far back the expression goes, and it doesn't indicate when it went from exclusively describing a physiological characteristic of horses to alluding figuratively to the advanced age of a person or other living creature or nonliving entity (such as RHEL 6 above).

  • 5
    It's 'long in the tooth'. Which means it's old. The expression comes from the fact that horses' teeth grow longer as they age. That's why you're not supposed to look a gift horse in the mouth.
    – Tushar Raj
    Commented Jun 27, 2015 at 11:05
  • 1
    The relative pronoun which refers to RHEL 6, whatever that is. Since the relative clause is nonrestrictive (i.e., the long in tooth attribute is not needed to identify one particular RHEL 6 as the referent, out of some multitude of RHEL 6s, but merely comments on the one and only RHEL 6), many of us would prefer to place a comma before which. Commented Jun 27, 2015 at 14:10
  • @BrianDonovan Thank you for the info. RHEL 6 is the name and version of a Linux operating system. So it makes sense to say it is a somewhat old fashioned operating system in that context.
    – Ely
    Commented Jun 27, 2015 at 14:14
  • 1
    I really wonder why someone would want to close the topic. What is off topic about it? English language & usage, isn't that right? There are excellent answers here which I'd have never been able to research myself. This is very demotivating, honestly.
    – Ely
    Commented Jun 27, 2015 at 23:05
  • 1
    Very well said @Elyasin
    – Avon
    Commented Jun 28, 2015 at 10:18

3 Answers 3


The phrase is referring to RHEL (Red Hat Enterprise Linux) 6. It is saying that RHEL 6 is somewhat old (and doesn't include the e2fsprogs package).

http://www.phrases.org.uk/meanings/long-in-the-tooth.html explains the meaning and origins of the phrase "long in the tooth":


Old, especially of horses or people.


Horses's teeth, unlike humans', continue to grow with age. They also wear down with use, but the changes in the characteristics of the teeth over time make it possible to make a rough estimate of a horse's age by examining them.

There are various similar Latin phrases dating back to the 16th century. The gap between these and the first citation of the English version - in 1852, make it likely that 'long in the tooth' was coined independently from those earlier Latin sayings. That earliest citation is in Thackeray's, The History of Henry Esmond, Esq. and refers to a woman rather than a horse:

"His cousin was now of more than middle age, and had nobody's word but her own for the beauty which she said she once possessed. She was lean, and yellow, and long in the tooth; all the red and white in all the toy-shops in London could not make a beauty of her."

Edit: phrases.org.uk's apparent (but not explicit) assertion that it comes from describing horses is debatable (but widely held). They undermine that argument themselves with their earliest citation, which describes a person.

That is of no consequence to the answer though. There is no doubt that "long in the tooth" means "old".

  • 2
    +1 for being first with the correct explanation. I plan to add an answer with documentation from additional sources, but this is the answer to upvote.
    – Sven Yargs
    Commented Jun 27, 2015 at 19:07

Additional corroboration for the "horse's teeth" origin that Avon's answer identifies:

From John Ayto, Oxford Dictionary of English Idioms, third edition (2009):

long in the tooth rather old

This phrase was originally used of horses, referring to the way their gums receded with age.

From Christine Ammer, The Facts on File Dictionary of Clichés, second edition (2006):

long in the tooth Aging or old. This unflattering term alludes to the fact that a horse's gums recede as it gets older, and transfers the same phenomenon to humankind. Th transfer understandably is not very old, since until relatively recent times adults who were old enough to experience gum recession generally had lost most of their teeth. It dates from the nineteenth century. Thackeray uses it in Henry Esmond (1852): "She was lean and yellow and long in the tooth."

From Robert Hendrickson, The Facts on File Encyclopedia of Word And Phrase Origins (1997):

long in the tooth That horses' gums recede and their teeth appear longer as they grow older, owing to their constant grinding of their food is the idea behind this ancient folk phrase, which means one is getting on in years.

Awareness of the age-related appearance of horses' teeth is also responsible for the saying "Never [or don't] look a gift horse in the mouth." Here is the discussion of that saying in J.A. Simpson, The Concise Oxford Dictionary of Proverbs (1982):

Never look a GIFT horse in the mouth. A horse's age is commonly gauged by the state of its teeth. The proverb warns against questioning the quality or use of a lucky chance or gift.

Simpson notes that this saying may be found in English found as early as Stanbridge, Vulgaria (1510): "A gyuen hors may not [be] loked in the tethe," and that St. Jerome uses essentially the same phrase in Latin in the preface to his Commentary on Epistle to the Ephesians in A.D. 420.

Nigel Rees, A Word in Your Shell-like (2004) confirms that the thing that a person may be checking when looking a gift horse in the mouth is the length of its teeth:

(to) look a gift horse in the mouth Meaning, 'to find fault with a gift or spoil an offer by inquiring too closely into it'. This proverb alludes to the fact that the age of horses is commonly assessed by the length of their teeth. If you are offered the gift of a horse, you would be ill-advised to look in its mouth. You might discover information not to your advantage.

Rees's conclusion seems a bit odd to me. The point of the expression, I think, is that any free horse is worth more than no horse at all, regardless of how long it is in the tooth—or how far it falls short of perfection—so that any vetting of the animal in front of the giver is a sign of foolish ingratitude.

Early matches for 'long in the tooth' in Google Books search results

A Google Books search finds several matches that are at least somewhat older than Henry Esmond (1852) for the phrase "long in the tooth." From Thomas Medwin, The Angler in Wales, or Days and Nights of a Sportsman, volume 2 (1836):

Though skittish, she [a mare] was only remarkable for the lowness of her action, and, what made her a favourite with her master, the consequent ease of her pace, the amble, her ordinary one. A brown gawky leggy Rozinante, very long in the tooth, and showing every bone in his skin, was generally ridden by his courier, though occasionally, by way of variety,, and to show the extent of the stud, he [the courier] was mounted on a black, entire, forest pony, who had acquired the mauvaise habitude of having his own way, and would frequently take it into his capricious head to quit the cavalcade, and return to his stable.

From Captain Bellew, "Memoirs of a Griffin," in The Asiatic Journal and Monthly Register (April 1841):

Yes, this [India] is the place for the man who wants a wife, an wishes to be met half-way, detesting, like me, the toil of wooing. There he can go, and if he sees a girl he likes, good forehand, clean about the fetlock-joints, free in her paces, sound and quiet, and not too long in the tooth, if not bespoke, he'll not find much difficulty in getting her.

The extended equating of a potential wife to a horse here is obvious. From Major Michel, Henry of Monmouth: or the Field of Agincourt, volume 1 (1841):

I tell you, dear honest David, that the squire of the most noble Earl of March is most deeply in love, and by the turn of that dear little girl's eye, I think it is reciprocal, and, forsooth, why not? We shall see : as if the old mother be sulky, why I will make love to her too, or perhaps, considering she is a little too long in the tooth for me, a friend might manage it instead.

From "The Norfolk Cob: A Celebrated Trotting Horse," in The Farmer's Magazine (October 1845):

As a stallion, perhaps the strongest proof of his excellence is the fact of his covering for fifteen seasons, in nearly the same circuit from which he was brought two years since by Mr. W. Howlett, Veterinary Surgeon, Bath, where he stood at Mr. Harvey's establishment, until the last few months, when he was purchased by Sir William Codrington, and sent out to his estates in the West Indies : rather long in the tooth, perhaps, for such a voyage, but still full of health and vigour.

And from Scribble, "My First Horse," in The Sporting Review (March 1846):

Away we went to cover ; and I had just time to see that I was on a perfect hunter, rather long in the tooth, but very short in the leg, when a hound challenged, and away went a fox for Middleton Park.

So of the earliest five Google matches, three exclusively involve actual horses, one assesses a hypothetical future wife as if she were a horse, and one is about a love interest's mother.

  • Interesting. So there does seem to be a weight of consensus behind the phrase initially referring to horses.
    – Avon
    Commented Jun 27, 2015 at 20:35
  • @Avon: Yep—and as you can see from the Google Books examples I've added to my answer, the earliest matches have a very horsey aspect.
    – Sven Yargs
    Commented Jun 27, 2015 at 21:09
  • Indeed but: 1836-Horse; 1841-Person; 1841-Person; 1845-Horse; 1846-Horse; 1852-Person. Nevertheless, that it should be used so commonly for horses and that there is a sound logic to it leaves me in no doubt from whence it came.
    – Avon
    Commented Jun 27, 2015 at 21:20
  • I would amend your list slightly to read as follows: 1836-Horse; 1841-Person-as-Horse; 1841-Person; 1845-Horse; 1846-Horse; 1852-Person. Descriptions of a person-as-person rarely take special note of the subject's "paces" and "fetlock-joints."
    – Sven Yargs
    Commented Jun 27, 2015 at 21:30
  • Good point! All the Persons are female too. Of course it's a very small sample, far too small to draw inferences from, but I will: it would undermine a Person origin if its not being used at that time to describe men.
    – Avon
    Commented Jun 27, 2015 at 21:39

What's this horse stuff? Is "The Phrase Finder" a recognized authority or is it like "Urban Dictionary," where they just go by consensus?

I am a dental assistant. (People teeth, not horse teeth.) As folks age, the gingival tissues shrink and recede. This makes the tooth structure appear much longer when a person is elderly, than when they are a young adult. Hence, "long in the tooth".

I'm not saying that the expression isn't used to describe horses - it just seems very unlikely that nobody noticed the old people's long teeth, and simply adopted the "horse phrase" to mean elderly person.

  • I'm inclined to agree but you haven't provided an answer to the question
    – Avon
    Commented Jun 27, 2015 at 17:22
  • @Avon- I'll edit for clarity...
    – Oldbag
    Commented Jun 27, 2015 at 17:45
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    phrases.org.uk do undermine their own argument when they cite The History of Henry Esmond as the origin and it is used there to describe a person. However, your answer is still ~70% rant and this isn't the appropriate place for that. If I were to delete my answer yours would look very odd without mine as context.
    – Avon
    Commented Jun 27, 2015 at 17:54
  • I'm going to speculate: Until recently, most people died or their teeth fell out before their gums receded because of age.
    – ab2
    Commented Mar 30, 2017 at 20:59

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