What does dex volume mean?

As a cryptocurrency enthusiast and finance professional, I'm often intrigued by the various metrics and terms that emerge in this rapidly evolving industry. One such term that I've encountered recently is "dex volume". Could you please elaborate on what this actually means? I understand it's likely related to decentralized exchanges, but I'd appreciate a more in-depth explanation of how it's calculated, what it signifies in terms of market activity, and perhaps even how it can be used as an indicator for investors and traders to make informed decisions. Thank you for your insight!