CoinDesk reported:
The BTC dominance rate is the BTC market capitalization’s share of the total market cap of the cryptocurrency market. The metric is important to assess the relative strength of BTC, the largest cryptocurrency by market value, compared to the broader crypto market, or identify periods when altcoins outperform, also known as an altcoin season. Ether dominance, similarly shows the second largest cryptocurrency’s relative value to the crypto market.