Hops question? what does this mean?

I was taking a look at the beersmith program. It's pretty neat. Under the hops use section here are the ways you can use them. What does number 4 mean? Number 1 is just boiling so 4 is?

1.Boil - Hops is boiled in the main boiler
2.Dry Hop - Hops is added "dry" to the fermenter (usually the secondary) to add aroma to the beer.
3.Mash Hop - Hops is added to the mash tun. This adds a lot of aroma to the beer, but only a small amount of bittterness.
4.First Wort Hop - Hops is added to the boiler as the first runnings are drawn from the lauter tun, and left during the boil. This added "steeping time" adds some bitterness and aroma to the finished beer.
5.Aroma (Steep) Hops - Hops that are steeped in the wort at the completion of the boil for aroma purposes only. Steeped aroma hops add no bitterness.

It's just adding hops to the wort before you start heating it. I've had a few brews that used FWH, but honestly, can't say there was anything noticeably different.

Thanks. I've got another question and hopefully someone can help.

I boil all my materials in a 2 gallon batch and then combine in the fermentation bucket later with the rest of my water. If I boiled a 4 gallon batch and then combine with one gallon but with the same amount of ingrediants would this increase the IBU? Basically, does boiling hops in a larger volume release more AA (bitterness)?

Thanks

Yup. Can't tell you exactly how much, but the lower the gravity of the boil (i.e. more water), the higher the utilization.

The larger the boil the more effective the extraction of the oils and other flavors from the hops.. When I first started brewing I messed with the full boil vs the partial boil and found a BIG difference in flavors with the larger boils being more bitter and more hop flavors present...

You will increase the IBU about 60%, so a 30 IBU 2 gallon boil becomes a 48 IBU 4 gallon boil.

Cool. Thanks