You know that glazed over look when people start using terminology you've never heard before? We're all guilty of our own jargon from time to time, using insider abbreviations, practically talking in code while the hapless onlooker just tries to look like they're with you? Doesn't feel awesome, does it?
Unfortunately it's really easy to do where you're talking about something as specialized as weddings, especially wedding dresses. And since not all designers/seamstresses/stylists are trained the same way, we all use different words too! So, what do you really NEED to know about fabric/cut/color/style? Well, most of the time all you need to know is if you like it or not! If a dress is double-faced satin organza or if it's principessa duchessa hot-messa doesn't change if it's YOUR dress. Well, usually, here's the only time it should:

Fabric VS Weave
Satin is not a fabric..well, okay, satin does not refer to the fabric material itself (you can't make a fabric by using satin), satin is the weave. So you can take silk thread and make that into satin, or you can take hot polyester mess and make it into satin. Ask your stylist what the fabric is; if they say satin, ask, "silk satin?" If it's "just satin" that's code for "synthetic fibers that won't breathe and weigh 8 billion pounds".
Same goes for organza, taffeta, and tulle (more to come on tulle in a second), they can all be made out of silk, or the cheap stuff, so ask about silk.
*random useless fact: almost all organza comes from one of four areas: the Yangtze River in China, or France, Italy, and Turkey. Lower quality organza is also made in northern India.

Bobbinet is machine made tulle, and unless it costs $4000 a yard and you can tell it's hand woven, the tulle/net/whatever on your dress or veil is bobbinet. What does that mean? Well, not much. But if someone is trying to sell you on something tulle vs. bobbinet, they don't know what they're talking about. True, there's varying levels of fine-ness of tulle, but it's all the same thing.
*random useless fact: Tulle is thought to have originated in or around Tulle, FR in the 18th century. This is why tulle appeared in ballet costuming in France, well before it became popular in other countries.

Not all silks are equal
Yes they're all silk, but have they been treated with chemical dyes? Have they been spun paper thin? Too thin to hold its shape or stand up the the structure of the garment? Trust your hand and your eye. If there's a soft natural glow to the fabric, you've got good stuff. Too hard or chintzy a sheen, it'll look striped in pictures. And fabric should feel good. Tulle petticoats can be scratchy, but if you find a gown that's full, feather weight, and the tulle feels fantastic, you've got yourself a winner!
*useless fact time (you may remember this from home ec.): the feeling of a fabric is called the "hand". If a fabric feels different in one direction, that fabric has a "nap"

Ivory is Arbitrary
There's buttery ivory, golden ivory, blush ivory, crisp ivory, strong ivory, pale ivory, deep ivory, light ivory, true ivory, rich ivory, soft ivory...and none of those mean anything either. It's like the names of white paint...there's no set rule as to what is called what. So you may be thinking "first snowfall" and I may have "spring lamb" and when it comes in it's "santorini villa". I love my card-carrying Pantone swatch girls, but at a certain point, there's no way to get an exact match, especially across different fabrics/materials with different sheen levels. Embrace tints and shades, small variations lighter and darker that add depth and beauty to color, and don't obsess too much about getting "just the right color"
*final useless fact: i used to wish i could get a job naming colors for someone like Benjamin Moore. I actually get special emails from them and other people, like Pantone, about color trends...yep, I'm that much of a color nerd!