rather strange. in dictionaries i can only find the meaning of 'grove' as small woods, but the term in 'tongue and grove' used in carpentry clearly means a place carved in.
why there is no such explanation in dictionary, or only i failed to find it?
Hello Pchuang

I can't find "grove" as an alternative spelling of "groove" in any dictionary. So if "groove" in "tongue and groove" is spelt "grove" on any websites, it's a little strange. I'm inclined to think it's a spelling mistake.

Grove is definitely a spelling mistake.

'Tongue and groove' comes from the way that these piece of timber are designed to slot together - on one edge is a tongue of wood (a piece sticking out) and on the other edge is a groove (a channel cut into the wood). The tongues slot into the grooves.
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Dear Pchuang,

It is perhaps «tongue and groove». Emotion: smile

There is a picture:-


Kind regards, Emotion: smile

thanks very much.
i have checked a few places in google, and found that there are two ways of spelling: grove and groove.
 MrPedantic's reply was promoted to an answer.
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 nona the brit's reply was promoted to an answer.
the correct spelling is indeed 'groove'.
thanks guys!