Now that's a pier, one of  the most photographed in San Diego.

I think of pier and post ... as in a foundation. 

Very familiar with this.  I remember many years ago when I was buying a home on the river, the banker called me and said they were going to have to re-evaluate my loan because of the post and pier foundation.  "What?  We have a full concrete foundation", I said.  Turns out the appraiser did the house down the street.  Goofball.  

A point of support usually made of of block, concrete or steel.

Where the boat is parked just a short distance from the mansion of my dreams.

I agree with Corinne Guest, Managing Broker, especially where she prefers walking on vacatons! 

The others have answered.

A place for fishing.

It is what goes in the ground or in the water.

Isn't that a southern fruit tree?

Awww...it looks like several people have beat me to the answer. 

If you remove it, your Jacuzzi falls through the ceiling onto your Open Space kitchen!

It is a place where a jerk stands with a stick and some string waiting for a jerk on the other end.

A place to go fishing from.

That's what Fisherman's Wharf is on in SF.

simply stated, a pier is a structural member.... whether it be on a bridge or dock or a deck/porch.... 

It appears many of my peers have answered correctly.