From Dungeons and Dragons Wiki
|This material from the 5th edition SRD is published under the OGL|
|A Hit Die represents a type of die (d6, d8, d10, etc.) that a creature has its hit points based on. I.e. if a creature has 6d8 hit dice you would roll 6 d8's and add the total (plus constitution modifier) to get the total hit points.
Adventurers (and some creatures) can "spend" a hit die during a short rest to regain a number of hit points back (up to it's hit point maximum). Half of these spent hit dice are restored at the end of a long rest.
|The material in this box is either SRD content from other sections or inferences drawn from SRD material in other sections. It should not be considered part of the core SRD, and is added only for clarity.|