Is the word "past" for time or for place?

Great question! Like many words in English, the word past has multiple meanings as well as multiple parts of speech. There are meanings for past that are related to TIME, and there are other meanings that are related to PLACE. Below are the most common uses and meanings of past, organized by part of speech. 

Noun

As a noun, past means  "a TIME long ago,” as in these examples:

•        In the past, there was a company luncheon every month. 
•        She wants to forget about the past. 

Preposition

As a preposition, past sometimes means “beyond or farther than a PLACE,” as in these examples:

•        The office is two blocks past the intersection. 
•        We drove past the house. 

The preposition past can also mean “beyond or later than a specific TIME” as in these examples: 

•        It’s past 7:00. We’re late.
•        It's past his bedtime. 

Adjective

As an adjective,  past can mean either “from an earlier TIME” or “from a TIME that just ended.”

•        The museum displays artifacts from past civilizations. [past = from an earlier time]
•        She was hired based on her past experience in marketing. [past = from an earlier time]

•        He has worked there for the past few months. [past = from a time that just ended]
•        I spoke with him this past [=last] weekend. [past = from a time that just ended]

I hope this is helpful.