hook
     n 1: a catch for locking a door
     2: a sharp curve or crook; a shape resembling a hook [syn: {crotchet}]
     3: anything that serves as an enticement [syn: {bait}, {come-on},
         {lure}, {sweetener}]
     4: a mechanical device that is curved or bent to suspend or
        hold or pull something [syn: {claw}]
     5: a curved or bent implement for suspending or pulling
        something
     6: a golf shot that curves to the left for a right-handed
        golfer; "he tooks lessons to cure his hooking" [syn: {draw},
         {hooking}]
     7: a short swinging punch delivered from the side with the
        elbow bent
     8: a basketball shot made over the head with the hand that is
        farther from the basket [syn: {hook shot}]
     v 1: fasten with a hook [ant: {unhook}]
     2: rip off; ask an unreasonable price [syn: {overcharge}, {soak},
         {surcharge}, {gazump}, {fleece}, {plume}, {pluck}, {rob}]
        [ant: {undercharge}]
     3: make a piece of needlework by interlocking and looping
        thread with a hooked needle; "She sat there crocheting all
        day" [syn: {crochet}]
     4: hit a ball and put a spin on it so that it travels to the
        left
     5: take by theft; "Someone snitched my wallet!" [syn: {snitch},
         {thieve}, {cop}, {knock off}, {glom}]
     6: make off with belongings of others [syn: {pilfer}, {cabbage},
         {purloin}, {pinch}, {abstract}, {snarf}, {swipe}, {sneak},
         {filch}, {nobble}, {lift}]
     7: hit with a hook; "His opponent hooked him badly"
     8: catch with a hook; "hook a fish"
     9: to cause (someone or oneself) to become dependent (on
        something, especially a narcotic drug) [syn: {addict}]
     10: secure with the foot; "hook the ball"
     11: entice and trap; "The car salesman had snared three
         potential customers" [syn: {snare}]
     12: approach with an offer of sexual favors; "he was solicited
         by a prostitute"; "The young man was caught soliciting in
         the park" [syn: {solicit}, {accost}]
Source: WordNet® 2.0

hook n. A software or hardware feature included in order to simplify
   later additions or changes by a user. For example, a simple program that
   prints numbers might always print them in base 10, but a more flexible
   version would let a variable determine what base to use; setting the
   variable to 5 would make the program print numbers in base 5. The
   variable is a simple hook. An even more flexible program might examine
   the variable and treat a value of 16 or less as the base to use, but
   treat any other number as the address of a user-supplied routine for
   printing a number. This is a {hairy} but powerful hook; one can then
   write a routine to print numbers as Roman numerals, say, or as Hebrew
   characters, and plug it into the program through the hook. Often the
   difference between a good program and a superb one is that the latter
   has useful hooks in judiciously chosen places. Both may do the original
   job about equally well, but the one with the hooks is much more flexible
   for future expansion of capabilities ({EMACS}, for example, is _all_
   hooks). The term `user exit' is synonymous but much more formal and less
   hackish.


Source: The Jargon File