Within our set of dictionaries, there are a total of 37,807 10-letter words.
Every single letter in the dictionary has at least 50 10-letter words that begin with it. The lowest is Y. There are 52 10-letter words that start with Y, including YOURSELVES, YESTERYEAR, and YEARNINGLY.
At the other end of the scale, there are 4,351 10-letter words that start with S. These include words like SCIENTIFIC, SPECIALIST, STRUCTURAL, and SIMULATION.