verb
To make larger
To occupy space to a given point
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
See extend in Webster's New World Roget's A-Z Thesaurus II
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