What is a key line in drama?

Answer 1

The definition to a key line in drama depends greatly upon the context in which the question is framed.

In regards to the entirety of the dramatic piece, the key line could be one of two things: Either

a) The line (regardless of character delivering it) that sums up the meaning and message of the drama

or,

b) The climactic line that changes everything / reveals sudden meaning / begins or ends the tragic downfall of whomever, etc, etc.

If we are discussing a key line with respect to specific characters, a key line is that one line that sums up the personality and/or personal motivations of a given character. This line may not necessarily be delivered by the character to whom it refers.