Recent stats
A rating computed over a recent window of battles only, so it reflects how a player performs now rather than over their whole history.
Also known as recent WN8, 30 day stats, last 1000 battles.
An account's overall rating is cumulative and never forgets. Battles played while learning the game keep dragging it down years later, and a player who has improved will read as far worse than they are.
Recent stats fix that by scoring only a window, typically the last 24 hours, week, month or a fixed number of battles. A stats site can compute them because it snapshots each tracked account regularly and diffs two snapshots: the difference between them is a real set of battles, with real damage and real results.
The trade-off is sample size. A few hundred battles is enough to see a trend and not enough to be precise, so a recent rating swings much harder than a lifetime one. Read it as a direction, not as a verdict.