Inside out means with the inside on the outside: a jumper, socks or a bag. Its second common meaning comes in know something inside out: to know something thoroughly, in every detail. The title of the Pixar film Inside Out uses the same phrase.
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wear/put on + something + inside out; turn + something + inside out; know + something + inside out
- You've got your jumper on inside out: I can see the label.
- Wash dark jeans inside out so the colour lasts longer.
- Ask Maria about the new booking system; she knows it inside out.
What changed
First versionOur guide knows the old town like his five fingers.
RevisionOur guide knows the old town inside out.
Like his five fingers isn't an English expression, so a native speaker won't recognise it as a fixed phrase and will stumble over it. English expresses the same idea with know something inside out: to know something from the inside, down to the last detail.
Inside out means with the inside facing outwards, upside down means with the top at the bottom, and back to front means the front is at the back: Your T-shirt is back to front — the label is under your chin. All three describe clothes worn the wrong way, but each is a different mistake.
Your turn
You've put your socks on ___: the seams are on the outside.
Show the answer
inside out — The seams are on the outside, so the socks are inside out. Upside down means with the top at the bottom: that's how you turn a picture or a cup, not socks.
Write about a task or place you know better than anyone around you. Name it and explain how you came to know it so well.
I know our office software inside out because I helped set it up three years ago.
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