“To be on top of sth” is an idiom that means “to be in control of a situation” or “to be fully informed about something.” It’s frequently used to assure someone that a problem or task is under control and is being dealt with appropriately.

Likewise, Christina uses this idiom in today’s dialogue to assure her boss that the team is in control and the work is being done.

The idiom “to be at a/the crossroads” means to be at a point in which an important change happens or decision must be made. For instance, “As a new graduate, I’m at the crossroads. I can choose to find a job or continue on to a master’s degree.“

The relative pronoun “where” can also be added to this phrase to further explain the situation. For instance, “As a business, we’re at the crossroads where we need to decide if we want to play it safe or start taking risks.“

Likewise, in today’s lesson, the speaker said, “It seems we’re at a crossroads where consumption patterns and technology have met in a serendipitous way.” Here “the crossroads” refers to the point at which consumption patterns and technology have met to create a good change.

In today’s lesson we learnt that part of Amazon’s mission statement is to be customer-centric. What they mean is that they believe in putting the customer first, or regarding the customer as the most important.

Centric is used quite commonly in physics and astronomy. In ancient times, people believed that all of the stars and planets revolved around the Earth. This is what is known as the “geocentric” model. A model where the Earth revolves around the Sun by contrast is called “heliocentric.“

Whenever you want to express putting someone or something first, putting them in the center, or regarding them as the most important thing, you can use “-centric.” It doesn‘t really matter if you use a hyphen or not, although if you are being creative and making your own word, it’s usually safer to use one.