Block time refers to the time taken for mining a single block of the cryptocurrency or verifying all the transactions present on a single block.
source https://www.google.com/url?rct=j&sa=t&url=https://www.btcwires.com/round-the-block/what-is-block-time-in-cryptocurrency/&ct=ga&cd=CAIyGmM2Nzk3ODA2ZWViNjVjODI6Y29tOmVuOlVT&usg=AFQjCNGyGhPi-PXs2NrnKS_XXsLrryL6hg
