Extant means still existing, surviving, especially said of a document. Extant comes from the Latin word extantem meaning stand out, be visible, exist. Extant is an adjective, it means more than merely existing, it implies survival. Something that is extant is something that is “still in existence”.
Extent means the scope of something, the degree to which something has spread, an expanse, the limit that something has reached. Extent is a noun, it comes from the Latin word extendere which means to spread out, spread.
Examples
In this tote was some material she had forgotten about: unpaid bills, bail receipts, letters from prison and a few extant fragments of hastily scrawled in situ field notes. (The New York Times)
Consequently, they chose to begin their national saga both by demythologizing the then current creation stories extant in the ancient Near East and asserting, though not consistently or in philosophical terms, the idea that there was and ought to be order in the universe, an order established by a single, powerful god. (The Jewish Journal)
Agree to suspend extant licences for the export of military equipment and technology to Saudi Arabia for possible use in Yemen pending the outcome of a full review as to whether the export of military equipment is compatible with EU arms control legislation. (Pravda)
The resident welfare association and citizen groups in Kudlu Gate, Haralur, Haralukunte, Somasundarapalya and Parangipalya have decided to conduct an environment study to determine the extent of pollution. (The Deccan Herald)
Officials from agencies in Blue Earth, Nicollet and Brown counties held a new conference Wednesday in St. Peter highlighting the extent of sex trafficking and their response to it. (The Mankato Free Press)
Facing Congress criticism that his meeting with Sonia Gandhi on GST issue was mere “optics”, Parliamentary Affairs Minister M Venkaiah Naidu on Friday said that government is willing to accommodate the views of Congress party “to the extent feasible.” (The Navhind Times)