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]