Main Entry: ex·ten·sion

Pronunciation: \ik-ˈsten(t)-shən\

Function: noun

Etymology: Middle English, from Late Latin extension-, extensio, from Latin extendere

Date: 15th century

1 a : the action of extending : state of being extended b : an enlargement in scope or operation <tools are extensions of human hands>
2 a : the total range over which something extends : compass b : denotation 4
3 a : the stretching of a fractured or dislocated limb so as to restore it to its natural position b : an unbending movement around a joint in a limb (as the knee or elbow) that increases the angle between the bones of the limb at the joint — compare flexion 4a
4 : a property whereby something occupies space
5 : an increase in length of time; specifically : an increase in time allowed under agreement or concession
6 : a program that geographically extends the educational resources of an institution by special arrangements (as correspondence courses) to persons otherwise unable to take advantage of such resources
7 a : a part constituting an addition b : a section or line segment forming an additional length c : an extra telephone connected to the principal line d : a length of natural or synthetic hair that is worn attached to one's natural hair e : a series of usually three or four characters following a dot at the end of the name of a computer file that specifies the file's format or purpose
8 : a mathematical set (as a field or group) that includes a given and similar set as a subset