1. adjective /bæk/
a) Near the rear.
Go in the back door of the house.
b) Not current.
I’d like to find a back issue of that magazine.
2. adverb /bæk/
a) (Not comparable) To or in a previous condition or place.
He gave back the money.
b) Away from the front or from an edge.
He needs his money back
3. noun /bæk/
a) The rear of body, especially the part between the neck and the end of the spine and opposite the chest and belly.
Could you please scratch my back?
b) The spine and associated tissues.
I hurt my back lifting that dictionary.
4. verb /bæk/
The train backed into the station.
b) To support.
I back you all the way.
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