30d is an abbreviation that denotes a 30-day timeframe (~approximately 1 month)
It is an abbreviation that exists far beyond cryptocurrency and digital assets alone and touches all open financial market;
Other Popular timeframe Denominations in open markets:
1hr – 1 hour
2hr – 2 hour
4hr – 4 hour
6hr – 6 hour
8hr – 8 hours
12hr – 12hours