Trunks are the most common and popular types of men's swimwear. I absolutely love how they fit and how versatile they are for so many water activities. Plus, you can always wear them as shorts unlike speedos or square-cut shorts.
I honestly don't think I have worn these since I was 17. They tend to have a looser fit with velcro fly and generally fall past the knee. It's originally meant for surfing, but people usually wear wetsuits for that these days.
These are essentially boxer briefs of swimwear. They offer more coverage than swim briefs and are shorter and fitter than trunks. They tend to be a lot fitter even with the drawstrings so most of the time I wear them for morning dips.
Most people refer to them as speedos. They are more on the revealing side but offer excellent support and fit. It brings more focus to your thighs hence making them sexier than other styles.