Funding Rate
A periodic payment between holders of long and short perpetual futures positions, set so the contract price tracks the spot price. When it is positive, longs pay shorts.
A perpetual future has no expiry and therefore no mechanism forcing it back to spot, so the funding payment supplies one: if the contract trades above spot, holding a long costs money until the gap closes. The rate is consequently a direct reading of which side is crowded and what it costs to stay there — a persistently high positive rate means leveraged buyers are paying for the privilege, which is information about positioning rather than about value.