something is missing…

i knew that a set of three periods was called an ellipsis, but i always found it to be an odd name because it sounds to much like 'ellipse' (a synonym for oval.)

but ellipsis actually has three meanings:

• ellipsis as punctuation to indicate an intentional omission from the original text. this is usually done with three periods, or a precomposed triple-dot glyph (like the single character in the title of this post - try highlighting just one period)
• ellipsis as an umbrella linguistic term for the common omission of words in cases where key information is already known. for example: "i'm tired. you?" instead of the longer, "i am tired. are you tired?"
• ellipsis as a narrative device where a story has an omission or gap that either condenses time or stylistically allows the audience fills in the gap with imagination. a simple example is anytime the characters in a story all go to bed. the story typically continues when they wake up, and you are left to fill in the detail that they were asleep the whole time.
  

it is easy to see that these three definitions all involve omission of some kind, and that is no surprise because they all come from the same greek word ἔλλειψις (élleipsis), which means omission. even the shape, ellipse, comes from this same root, and can be created by omitting part of a cone or cyllinder.

as a bonus - you may notice my example of linguistic ellipsis uses the contraction "i'm." there is another english word that is a child of élleipsis, and that is elision. elision describes the omission of letter sounds when you speak a word (e.g. most all of french) and while contractions are not truly elision because they have become actual words, the concept is the same...