Block top - The block selection and size with the blockchain (in blocks) on generation of the present block Nonce - The transaction selection for the from address (bear in mind this starts at 0 so a nonce of 100 would really be the 101st transaction submitted by this account) https://bookmarkpagerank.com/story20330280/the-greatest-guide-to-blockchain-explorer-unconfirmed-transaction-https-writeablog-net-storeformat0-blockchain-in-the-microscope-exploring-the-unsung-resources