Definition of book hand:
(n) :
a
stroke made across the chest from the
off-hand side to the
racquet hand side; a stroke during which the back of the hand faces the shot; handwriting that leans to the left
(v) :
to execute a backhand stroke or throw; to slap with the back of ones hand
(adj) :
(handwriting) any left slanting handwriting; (of strokes or throws) in the backhand style
"he scored on a backhand shot."