lacune

Etymology
From. .

Noun

 * 1) A lacunar stroke or infarct.
 * 2) A lacuna.
 * 1) A lacuna.

Noun

 * 1) a gap
 * 2)  something that is missing

Etymology
..

Noun

 * 1) gap
 * 2) vacuum, empty space
 * 3)  lack; thing that is missing
 * 4)  ignorance, shortcoming