Q&A: The origin of “fine-tooth comb”

Each week here at the Australian Writers’ Centre, we dissect and discuss, contort and retort, ask and gasp at the English language and all its rules, regulations and ridiculousness. It’s a celebration of language, masquerading as a passive-aggressive whinge about words and weirdness. This week, comb and get it…

Q: Hey AWC, my friend was talking about losing her keys and having to search her house with a “fine-tooth comb” the other day. And it got me thinking.

A: About where her keys would be? 

Q: No, about why we have such an idiom. Is a “tooth comb” like a toothbrush?

A: Ahhh haha, well you’ve got it all mixed up from the beginning. The comb in question is not one made for teeth, but rather it is made from fine teeth! 

Q: Oh, of course – that makes a lot more sense!

A: Yes. The name seems to have arrived with the product itself – in 1836 – and it describes a specific type of metal comb used for combing out head lice. Any parent of a school-aged child may recognise the kind!

Q: Now you’re just nit-picking.

A: Indeed. And by the way – to avoid any ambiguity, the term should always include a hyphen. It was originally a “fine-toothed comb” but these days has been shortened to “fine-tooth comb”. 

Q: No combing of teeth required.

A: Precisely.

Q: It still doesn’t explain how we got from killing lice to searching for keys.

A: True. The fine-toothed comb started its life doing its originally intended job.

Q: It did a lousy job!

A: Very good. So do you know when it made the leap from lice to other things?

Q: Not off the top of my head!

A: Groooan. It appears to have been around the latter part of the 1800s that fine-toothed combs stopped being a literal object that you ran through hair and became a figurative phrase meaning to search for ANYTHING with great care.

Q: I suppose it wasn’t much of a leap after all.

A: Not really. Merriam-Webster’s dictionary has two listings for “fine-tooth comb”. The first is that comb with fine-set teeth used to eradicate parasites, while the second is the more figurative “attitude or system of thorough searching or scrutinising”. The example for this that they give is to “go over a report with a fine-tooth comb”.

Q: It’s basically just a way of saying “I’m looking very closely”

A: That’s right. The verb “comb” came to mean “search” around 1904 – such as “they combed the woods and searched every warehouse, farmhouse, henhouse, outhouse and doghouse”.

Q: Are you quoting Tommy Lee Jones in 1993’s The Fugitive?

A: Perhaps.

Q: Okay, so to recap – it started out as a device to catch tiny bugs, but today it can also simply mean a really thorough search. And the whole thing has nothing to do with flossing or picking at your teeth, yeah?

A: That’s right! Hey – did your friend find their keys?

Q: Yes, and would you believe they were in the last place they looked!

A: Of course. They’re always in the last place – as the search would then be over, yes?

Q: Okay, now you’re just being too logical…


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