to spread or stretch (something) forward
to stretch (something) out to its fullest length
to give or offer (something), usu in response to need
to lengthen or enlarge (a building, etc)
to prolong (something) in time
to increase the scope, meaning, or application of (something)
to cause (power, authority, etc) to apply in a particular place
to advance or further (knowledge, etc)
to exert (a horse, oneself, etc) to full capacity
to apply or be valid over a distance or time
extendable adj
extendible adj
[Middle English extenden via French from Latin extendere, from ex-1 + tendere to stretch]