I'm sorry, what lens did you say? (boring alert)

In my last post I listed the 2 different kinds of lens' that I have.
And I have no idea what it means. Maybe one is bigger than the other?
So I researched it and now I'm going to break it down for myself. And for you if you are clueless like me =)
This will be long and perhaps boring if you know this.

We will start with:

AF-S DX Nikkor 18-105mm f/3.5-5.6G ED VR

AF-S: An Auto Focus lens with a Silent Wave Motor. Apparently the Silent Wave technology uses ultrasonic vibration to allow the camera to focus both more quietly and steadily. Sounds good to me. {more here} Nikkon is upgrading it's AF lenses with the Silent Wave feature.

DX: This refers to the type of image sensor which determines the field of view that a camera can capture. My Nikon D90 is a DX camera. Apparently you can choose between a DX or an FX - FX's are top of the line, have a larger field of view and will be much more expensive (Nikon bodies starting at 3,000 and Canon bodies starting at 1900). From what I read you can use an FX lens on a DX camera and vice versa but that's over my head right now and I'll just stick to my lenses =) (more here and here)

Nikkor: Brand of lens produced by Nikon.

18-105mm: a "light do almost anything" "general purpose" lens (+). The mm refers to magnification capabilities. If this hadn't come with my D90 "kit", from what I read there are other lenses that make more sense financially (like the 18-200 and/or the 18-55). However, this lens is the "walking around" choice for David Busch. Indebted to kenrockwell.com for my knew lens knowledge =)

f/ 3.5-5.6: refers to "focal ratio, f-ratio, f-stop, or relative aperture". The F number refers to the hole in the lens that lets light in. Faster f/stops are lower numbers.  We want a faster f/stop lenses will let in more light in the dark. (here & here). The numbers involve a lot of ratios/math which I am not good at so I think I will just be experimenting and getting a feel for these  =)

G: Stands for 'Gelded' which means castrated. The aperture ring has been removed to save cost and they will not work on manual focus cameras. (source)

ED: (Extra low dispersion) This indicates lens elements made of a hard and scratch resistant glass that minimizes image defects. The colors are passed through this lens with minimal divergence - keeps the colors crisp I guess! (source)

VR: A feature that shifts lens elements internally to counteract camera shake. Helps to avoid the need for a tripod. And K. Rockwell says it allows for better pictures in dim lighting using a longer exposure (which I seem to do a lot of, so this is good!). Also, this feature should be turned off when using a tripod. (here & here)

And now

AF-S DX VR Zoom-Nikkor 55-200mm f/4-5.6G IF-ED

Everything on this lens is similar besides the mm size, f/stop size and the fact that it is designated as IF. 

IF: (Internal Focus) Means that lens focuses by shifting small internal lenses with no change required in the physical length of the lens. These tend to be more compact, light, provide better balance, and focus more closely and quickly. (source) Also reduces risk of the lens hitting the object that you are focusing on up close (source)

55-200mm: "Telephoto lens of the decade" This lens gets high reviews from Ken Rockwell's website.