extension in WordNet English dictionary

1. an addition that extends a main building
   annex  annexe  extension  wing 
   
2. the most direct or specific meaning of a word or expression; the class of objects that an expression refers to
   "the extension of `satellite of Mars' is the set containing only Demos and Phobos"
   reference  denotation  extension 
   
3. an addition to the length of something
   elongation  extension 
   
4. an educational opportunity provided by colleges and universities to people who are not enrolled as regular students
   extension  extension service  university extension 
   
5. act of stretching or straightening out a flexed limb
   extension 
   
6. act of expanding in scope; making more widely available
   "extension of the program to all in need"
   extension 
   
7. an additional telephone set that is connected to the same telephone line
   extension  telephone extension  extension phone 
   
8. amount or degree or range to which something extends
   "the wire has an extension of 50 feet"
   extension  lengthiness  prolongation 
   
9. the ability to raise the working leg high in the air
   "the dancer was praised for her uncanny extension"; "good extension comes from a combination of training and native ability"
   extension 
   
10. a string of characters beginning with a period and followed by one or more letters; the optional second part of a PC computer filename
    "most applications provide extensions for the files they create"; "most BASIC files use the filename extension .BAS"
    extension  filename extension  file name extension 
    
11. the spreading of something (a belief or practice) into new regions
    propagation  extension 
    
12. a mutually agreed delay in the date set for the completion of a job or payment of a debt
    "they applied for an extension of the loan"
    extension