One staff member's synthesis of sustainability:

Sustainability: Maintenance and support of renewable resources

Notes: sus.tain (s?-sta-n')

tr.v. sus.tained, sus.tain.ing, sus.tains

To keep in existence; maintain.
To supply with necessities or nourishment; provide for.
To support from below; keep from falling or sinking; prop.
To support the spirits, vitality, or resolution of; encourage.
To bear up under; withstand: can't sustain the blistering heat.
To experience or suffer: sustained a fatal injury.
To affirm the validity of: The judge has sustained the prosecutor's objection.
To prove or corroborate; confirm.
To keep up (a joke or assumed role, for example) competently.

[Middle English sustenen, from Old French sustenir, from Latin sustine-re : sub-, from below; see sub- + tene-re, to hold; see ten- in Indo-European roots.] sus.tain'a.bil'i.ty n.,

sus.tain'a.ble adj., sus.tain'er n., sus.tain'ment n.

sus.tain.a.ble (s?-sta-'n?-b?l)> adj.
Capable of being sustained.
Capable of being continued with minimal long-term effect on the environment: sustainable agriculture.> sus.tain'a.bil'i.ty n.

The American HeritageR Dictionary of the English Language, Fourth Edition Copyright C 2006 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.