Block top - The block selection and length of the blockchain (in blocks) on creation of the current block Nonce - The transaction number 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://bookmark-media.com/story20821176/what-does-blockchain-explorer-usdt-mean-https-pad-fs-lmu-de-h2fzbno0rjqfpyic-69lxg