Have you got hair extensions?
In this instance, the word ‘extension’ means to make longer. ‘Extension’ has other meanings as well. (‘Extension’ is the noun and ‘extend’ is the verb).
a) an extension to a building is a part added to a structure to enlarge it.
b) An extension lead or cable is a length of electrical which permits the use of appliances at some distance from a fixed socket.
Can you think of other meanings of the word ‘extension’?