It really depends on the context. A word may vary in meaning among others in this following categories
1) The context of what is being said.
Example a) Holy Cow b) The cow will be sacrificed for the feast.
2) The word being used in the absolute sense or it's derivation.
Example a) I came from Brad's Marriage
b) Brad and Linda bonded in a Marriage today
With this context, the word Asr may have various meaning. One really need to understand and master the Arabic of the 7th century arabia to know the meaning of this word in the verse of this ayath. In this verse it means time to signifies the phase of history starting from the Prophet Adam (sws) and ending on the Prophet Muhammad (sws) in which a series of Prophets were sent by the Almighty to reveal the truth in its ultimate form. The most distinct feature of this phase of history was that whenever nations rejected the Prophets sent to them, they were destroyed.