extent (n.)

c. 1300, extente, "tax levied on value; value of property for taxation," from Anglo-French extente, estente "extent, extension;" in law, "valuation of land, stretch of land," from fem. past participle of Old French extendre "extend," from Latin extendere "to spread out, spread" (see extend). Meaning "degree to which something extends" is from 1590s.