Customer Purchase Latency is a measurement of the delay between customer purchase events (orders). It's in the form of a time, usually a number of days. So a 30 day Customer Purchase Latency means 30 days pass between orders.
This is usually aggregated across all of your customers into Average Customer Purchase Latency.
Eric Davis
Customer behavior analysis for better Shopify store performance
The Shopify App that increases repeat customer purchases through customer behavior analysis.