Iota

I*o"ta (?), n. [L., fr. Gr. 'iw^ta. See Jot.]

1. The ninth letter of the Greek alphabet (ι) corresponding with the English i.

2. A very small quantity or degree; a jot; a particle.

They never depart an iota from the authentic formulas of tyranny and usurpation.
Burke.

Iota subscript (Gr. Gram.), iota written beneath a preceding vowel, as a,, h,, w,, -- done when iota is silent.