The Collaborative International Dictionary of English v.0.48:

Bookland \Book"land`\, Bockland \Bock"land`\, n. [AS.
   b[=o]cland; b[=o]c book + land land.] (O. Eng. Law)
   Charter land held by deed under certain rents and free
   services, which differed in nothing from free socage lands.
   This species of tenure has given rise to the modern
   freeholds.
   [1913 Webster]

Bouvier's Law Dictionary, Revised 6th Ed (1856):

BOOK-LAND, English law. Land, also called charter-land, which was held by
deed under certain rents and fee services, and differed in nothing from free
socage land. 2 Bl. Com. 90. See 2 Spelman's English Works, 233, tit. Of
Ancient Deeds and Charters.