The Collaborative International Dictionary of English v.0.48:

Jot \Jot\, n. [L. iota, Gr. 'iw^ta the name of the letter [iota]
   (E. i, Heb. y[=o]d), the smallest letter of the Greek
   alphabet. Cf. Iota.]
   An iota; a point; a tittle; the smallest particle. Cf. Bit,
   n.
   [1913 Webster]

         Till heaven and earth pass, one jot or one tittle shall
         in no wise pass from the law, till all be fulfilled.
                                                  --Matt. v. 18.
   [1913 Webster]

         Neither will they bate
         One jot of ceremony.                     --Shak.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Jot \Jot\, v. t. [imp. & p. p. Jotted; p. pr. & vb. n.
   Jotting.]
   To set down; to make a brief note of; -- usually followed by
   down.
   [1913 Webster]

WordNet (r) 3.0 (2006):

jot
    n 1: a brief (and hurriedly handwritten) note [syn: jotting,
         jot]
    2: a slight but appreciable amount; "this dish could use a touch
       of garlic" [syn: touch, hint, tinge, mite, pinch,
       jot, speck, soupcon]
    v 1: write briefly or hurriedly; write a short note of [syn:
         jot down, jot]

Moby Thesaurus II by Grady Ward, 1.0:

167 Moby Thesaurus words for "jot":
   ace, atom, birthmark, bit, blaze, blemish, blotch, book, brand,
   calendar, carve, caste mark, catalog, chalk, chalk up, check,
   check in, checkmark, chronicle, cicatrix, crumb, cut, dab, dapple,
   discoloration, docket, dole, dot, dram, dribble, driblet, drop,
   droplet, dwarf, earmark, engrave, engraving, enroll, enscroll,
   enter, farthing, file, fill out, fleck, flick, flyspeck, fragment,
   freckle, gash, gnat, gobbet, grain, granule, grave, graving, groat,
   hack, hair, handful, impanel, incise, index, inscribe, insert,
   iota, jot down, lentigo, list, little, little bit, log, lota,
   macula, make a memorandum, make a note, make an entry, make out,
   mark, mark down, marking, matriculate, microbe, microorganism,
   midge, minim, minimum, minute, minutia, minutiae, mite, modicum,
   mole, molecule, mote, mottle, nevus, nick, notch, note, note down,
   nutshell, ounce, particle, patch, pebble, pinch, pinhead, pinpoint,
   pittance, place upon record, point, polka dot, poll, post, post up,
   prick, puncture, put down, put in writing, put on paper,
   put on tape, record, reduce to writing, register, scar,
   scarification, score, scotch, scrap, scratch, scratching, scruple,
   set down, smidgen, smitch, snip, snippet, speck, speckle, splash,
   splotch, spoonful, spot, stain, stigma, strawberry mark, tabulate,
   take down, tape, tape-record, tattoo, tattoo mark, thimbleful,
   tick, tiny bit, tittle, trifling amount, trivia, vanishing point,
   videotape, watermark, whit, write, write down, write in, write out,
   write up



Easton's 1897 Bible Dictionary:

Jot
   or Iota, the smallest letter of the Greek alphabet, used
   metaphorically or proverbially for the smallest thing (Matt.
   5:18); or it may be = yod, which is the smallest of the Hebrew
   letters.