The definition of the noun lacuna in English is :
1 An unfilled space; a gap.
1.1 A missing portion in a book or manuscript.
The definition of lacuna in medical terms:
2 A cavity or depression, especially in bone. 
The term “Lacuna” derives from the Latin for “hole” or “pit from lacus lake. It was first used to describe missing text and appeared in Lauderdale Papers (1884)  Sir Robert Moray wrote: “You do well to leave no lacunas in your letters”. Gaps in manuscripts (lacunas) can be done intentionally and unintentionally. Often decay and weathering to old passages of text can be responsible for lacunas. Alternatively lacunas can be used on purpose for example children’s books often have words missing in sentences blank spaces underlined for the student to them fill it in for educational purposes.
My interpretation of a lacuna is the modern day intentional use of lacuna to create a or enhance a human emotion whether its suspense , mystery or confusion. Music in history has often used lacunas as a extended passage in musical work during which no notes are played. The most famous example of this is John cages piece (4’33) that I consider a piece made entirely out of lacunas. 
A more modern example is Radio heads use of lacuna in their “Motion Picture Soundtrack”, the last track on the album “Kid A” . Radiohead’s use of heavy music is juxtaposed with this 2 minutes of silence . The song is 6:56 minutes long with silent gaps from 3:15—4:18 and 5:08 till the very end 6:56. Radio head have used lacuna as “negative music” to create a sense of serenity and build tension and it is a strong contrast to the “normal/heavy” music that plays after the silence and in the rest of the album. This forces the listener to pay attention and reflect on the way the song is delivered and performed rather than just the beat and music. 
After researching the term lacuna and its definition as well as examples of how it is used. I am taught the important of silence and gaps and the idea that having nothing there effectively making the listener or consumer come up with thoughts to fill the gap can be more effective in creating more off an impact. Silence and forcing someone to reflect with their own thoughts can or be me more powerful than filling it with with your own pre convinced thoughts.
 Oxford University Press. 2017. English oxford dictionaries: Lacuna. [ONLINE] Available at: https://en.oxforddictionaries.com/definition/lacuna. [Accessed 1 March 2017].
 Full text of “The Lauderdale Papers”. 2017. Full text of “The Lauderdale Papers”. [ONLINE] Available at: https://archive.org/stream/lauderdalepapers01camduoft/lauderdalepapers01camduoft_djvu.txt. [Accessed 1 March 2017].