Lacuna

Lacuna: a gap or hiatus, as in a manuscript.

This word, or rather lacunae is used in the book. It's a term I remembered vaguely from Lit studies but couldn't figure it out so thought I'd post a few different definitions and links to it....

Macquarie says it's:

"/luh'kyoohnuh, -'kooh-/ noun, plural lacunae /luh'kyoohnee/ or lacunas.
1. a pit or cavity; an interstitial or intercellular space as in plant or animal tissue.
2. Anatomy one of the numerous minute cavities in the substance of bone, supposed to contain nucleate cells.
3. Botany an airspace lying in the midst of the cellular tissue of plants.
4. a gap or hiatus, as in a manuscript."

From Wikkepedia: (http://en.wikipedia.org/wiki/Lacuna)
"A lacuna is a gap in a manuscript, inscription, text, or a musical work.
The word is Latin for hole or pit. The plural is lacunae. (The word lagoon referring to an empty space of water is cognate.)
The state of old manuscripts or inscriptions which have weathered or been damaged sometimes gives rise to lacunae - passages consisting of a word or words that are missing or illegible. In order to reconstruct the original text, the context is to be considered. In archaeology and literary criticism this may sometimes lead to competing reconstructions and consequent interpretations. "

It refers later to it's use in Linguistics - which I studied so I am assuming that's where I heard it:
Linguistics
"In translation, a lacuna is a lexical gap, a lack of one-to-one equivalence between the word, expression or turn of phrase in the source language and another word, expression or turn of phrase in the target language. This is a factor in untranslatability."