Extent, a.
Etymology: [L. extentus, p. p. of extendere. See Extend.]
Extended. [Obs.] Spenser.
1 other Webster entry under this spelling
Extent, n.
1. Space or degree to which a thing is extended; hence, superficies; compass; bulk; size; length; as, an extent of country or of line; extent of information or of charity. Life in its large extent is scare a span. Cotton.
2. Degree; measure; proportion. "The extent to which we can make ourselves what we wish to be." Lubbock.
3. (Eng. Law) (a) A peculiar species of execution upon debts due to the crown, under which the lands and goods of the debtor may be seized to secure payment. (b) A process of execution by which the lands and goods of a debtor are valued and delivered to the creditor.
Shades of meaning
Fernald has no entry of its own for extent; he lists it under end.
He lists it without comment; the entries above explain its neighbors.