Introduce vs Extend - What's the difference?

In lang=en terms the difference between introduce and extend

is that introduce is to bring (something) into practice while extend is to straighten (a limb).

is that introduce is (of people) to cause (someone) to be acquainted (with someone else) while extend is to increase in extent.

(introduc)

(of people) To cause (someone) to be acquainted (with someone else).

To make (something or someone) known by formal announcement or recommendation.

To add (something) to a system, a mixture, or a container.

To bring (something) into practice.

* {{quote-magazine, date=2013-10-05, volume=409, issue=8856, magazine=(The Economist)

, title= The widening gyre , passage=First introduced in Letchworth Garden City in 1909, the roundabout

(en verb)

To increase in extent.

To possess a certain extent.

To cause to increase in extent.

To cause to last for a longer period of time.

To straighten (a limb).

To bestow; to offer; to impart; to apply.

to extend sympathy to the suffering

To increase in quantity by weakening or adulterating additions.

to extend liquors

(UK, legal) To value, as lands taken by a writ of extent in satisfaction of a debt; to assign by writ of extent.

* enlarge * expand * increase * lengthen * stretch * widen

* extendible (adjective) * extensible (adjective) * extensive (adjective) * extension * extent