Block top - The block selection and duration of the blockchain (in blocks) on creation of the current block Nonce - The transaction number with 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://letsbookmarkit.com/story20229326/detailed-notes-on-blockchain-explorer-unconfirmed-transaction-http-bioimagingcore-be-q2a-user-storegarlic8