This will be referring to a take off alternate. You are required to have (when conditions don't allow a return to land at your departure aerodrome) an alternate within 60 mins single engine flight time. Practically you could use your blue line speed as a reference (on a light twin). Then have an alternate within that many NM. If your blue line speed (vyse) is 106 kts, have a suitable place to land within 106nm.
Being even more practical, you're probably best in most light twins to sit on the ground if the conditions are below landing minima. If you have an engine failure, the other one will more than likely take you to the crash site
