There are a couple of aliases or similar types in solidity that you should be paid attention.
- uint is alias to uint256.
- byte is alias to bytes1.
- sha3 is alias to keccak256.
- now is alias to block.timestamp.
- bytes is the same byte[] but packed tightly.
- string is almost the same as bytes but doesn't allow length or index access.
- address is equivalent to uint160