Date: Tue, 11 Nov 1997 23:19:57 -0600


Subject: Re: Rima's rule of thumb

This is dueling folk-etymologies.

Yep. OK, I'll put in my two cents.

But without being an expert on this bit of lore, all I can add is that if

you read the OED2 cites of "rule of thumb" (back to 1692) there's no mention

of or hints at beating anywhere. There is however almost always a sense that

"rule of thumb" means something inexact -- hardly the sense of the word in

the "beating" account, where the "rule of thumb" refers to the exact size

something can legally be. I have heard accounts that tie "rule of thumb" to

sailing (measuring the needed thickness of a rope for a given task when as a

sailor you have no ruler) and tailoring (using the width of the thumb to

measure without a ruler or the like -- get it? *rule* of thumb.... Cf. OED2

rock n.3, meaning 1b, where "rock/rack of eye and rule of thumb" is a

tailors' phrase for inexact measurement).

If anyone has the *real* story and the evidence, maybe s/he'd cough it up.

I've always assumed, and have heard so from others, that the rule of thumb

refers to the use of the last joint of the thumb to be an approximation of

an inch. It's not too mucn of a stretch to imagine a taylor or seamstress

measuring the distance from the tip of the thumb or index finger to a spot

that would be an inch from the tip and then using that spot in making "rule

of thumb" measurements. My mother used a spot about so far past the first

crease in the index finger on her left hand. And it's not too much of a

stretch to see sailors (or pirates) using the thickness of the thumb or the

length of the first joint to determine whether a rope would be strong

enough for certain tasks.

To me, assuming that the origin of the thumb-term has something to do with

beating one's wife is like assuming that "Have a nice travel" is the origin

of "have a nice trip." As for the latter, I can imagine someone hearing

another say 'I'm going to travel next week" and responding with "Have a

nice travel," even though it isn't the usual idiomatic expression.