Lacuna meaning : A small opening; a small pit or depression. A small blank space; a gap or vacancy; a hiatus. An absent part, especially in a book or other piece of writing, often referring to an ancient manuscript or similar. Any gap, break, hole, or lack in a set of things; something missing. A space visible between cells, allowing free passage of light. A language gap, which occurs when there is no direct translation in the target language for a lexical term found in the source language.