Can someone explain tea to me?

I've heard it's nothing more than the evening meal, or what we call "dinner" in the United States.  Is this true, or is it more than that?  Is there certain ettiquette involved?  What does a typical "tea" consist of besides tea?

Tea=dinner

It means different things depending on where you are in UK.
I am a Brit.  Where I was brought up dinner was a mid day meal and "tea" was an early evening meal. Supper was a mid evening snack before going to bed.

Where I live now (south east England) the mid day meal is lunch, and the evening meal is dinner.

I'm interested in this topic, too.  When I watch Richard & Judy it's on from 5-6pm.  Their big ad is Lee&Perins which tells me, 'Spice Up Teatime with Lee&Perins and Richard&Judy'.

If most people eat dinner from 5-6pm, then that is waay earlier than I know most Brits eat dinner. 

I think I'm just confused.  Sorry I'm not explaining myself well tonight.

Tea can also refer to 'afternoon tea' (around 4-ish) which can be a selection of cakes or finger sandwiches and tea.  I most often hear tea referred to as the evening meal.

My husband refers to the mid-day meal as "dinner" and the evening meal as "tea".  He's from South Wales.  Possibly it's regional?

Hubby's from the Northeast and all of his family use 'tea' too.

Fiancee is from the south-west; dinner is "tea" to him.

School lunch is often referred to as dinner.
There is even a comedy series called "Dinner Ladies" who prepare and serve lunches.

Sean used "dinner" to mean lunch, "tea" to mean dinner, "tea" to mean.. well, tea, "supper" to mean a late-night snack, "brekkie" for breakfast, "afters" for dessert, and "snack" for afternoon tea and biscuits or alternatively, chocolate milk and a ham roll. 


....
what? 

School lunch is often referred to as dinner.
There is even a comedy series called "Dinner Ladies" who prepare and serve lunches.

It was quite funny, too!