Code coverage means, how well your test set is covering your source code. i.e. to what extent is the source code covered by the set of Test cases. As mentioned in above answers, there are various coverage criteria, like paths, conditions, functions, statements, etc.
Chiasmus. Definition: Chiasmus is a specific type of parallelism. It consists of two parallel phrases in which corresponding words or phrases are placed in the opposite order.
Chiasmus (from Greek, cross or x): A literary scheme involving a specific inversion of word order. It involves taking parallelism and deliberately turning it inside out, creating a crisscross pattern. For example,, consider the chiasmus that follows: By day the frolic, and the dance by night..