extend

v.

1. To make larger

   lengthen, elongate, protract, stretch out, draw out, enlarge, prolong; see also increase 1.

2. To occupy space to a given point

   continue, go as far as, stretch, spread; see reach 1.

extend and lengthen both imply a making longer in space or time, but extend, in addition, may signify an enlarging in area, scope, influence, meaning, etc.; elongate is a synonym for lengthen in the spatial sense and is more commonly used in technical applications; prolong and protract both primarily imply an extending in time, prolong suggesting continuation beyond the usual or expected time, and protract a being drawn out needlessly or wearingly