The word "dash" has multiple meanings and can be used in different contexts.
1) In a sentence, it could refer to something that is done quickly or with great speed; for example, "He dashed out of the room."
2) It can also indicate a sudden change or interruption; as in, "There was a dash of color added to the otherwise dull painting."
3) In addition, "dash" could mean a short written statement that expresses an opinion or feeling; for example, "He left a dash on his Facebook status about how much he hated Mondays."