First

1) First 

Usage:

This is my first visit to New York.

I fell in love with him the first time I saw him.

I’m always nervous for the first few minutes of an exam.

When did you first meet each other?

He is the first (= very willing) to admit that much of his success is due to his good looks.

First of all / (First off) I’d like to ask you a few questions about your childhood. 

2) At first
In or at the beginning. 

Usage:

At first I thought he was joking but then I realized he meant it. 

3) In the first place
In or at the beginning (of a series of events) 

Usage:

The trousers shrank when I washed them, but they weren’t really big enough in the first place. 

4) First thing
At the earliest time in the day.

Usage:

He said he’d phone back first thing tomorrow. 

5) First-born (child)
The first child of a set of parents 

Usage:

Cherry is my first-born. 

6) First Class
i) Relating to the highest quality service on a plane, train, or in a hotel

She always travels first class. 

ii) Relating to the fastest mail service:

How much more would it cost to send it first class? 

7) Make the first move
 To be the first to take action. 

Usage:

She’s fancied him for ages, but doesn’t want to make the first move.