Blocks and dodges are functionally identical. The only reason some units/pirates block instead of dodge is the type of weapon they have. Both block and dodge are based off the dodge statistic. Armor reduces incoming physical damage.
The greater the amount of armor, the less damage the character takes. The greater the amount of dodge, the greater the odds of the player blocking/dodging is when attacked, although this number can be affected by how much accuracy the opposing character has.
Well, I know block and dodge are the same. I believe ranged attacks are dodged, magical attacks may be fizzled or dodged, and melee attacks can be dodged or blocked, depending on who is dodging. They don't have much difference, just the animation and the text.