Fat and TransFat

So I was eating Ranch crackers and noticed it said "0g TransFat" but "7g Total Fat" and "4g Saturated Fat" for a total of 12%. Which means there's 0g of TransFat but still 12% fat. I was like, "well, what exactly is the difference between FAT and TRANSFAT"? I did my research and this is what I found.

Saturated: carbon atoms have all the hydrogen they can hold. Saturated fats tend to be in solid form, like Crisco and butter.

Unsaturated: carbon atoms can hold more hydrogen. Unsaturated fats are typically liquid, like oils. Oils tend to separate from foods, while fats stay in place

Mono-unsaturated: only 1 carbon still has room for hydrogen

Polyunsaturated: many carbons have room for hydrogen.

If the food has less than half a gram of trans fat, it can be called trans fat free.

"However, just because a food is trans fat free or high in polyunsaturated fat does not necessarily mean it is good for those watching their weight. All fats have 9 calories per gram compared to 4 calories per gram for carbs and protein. "