Deployment: typically a combat deployment runs 6–12 months long. You are in country doing your job whatever it is with very little time off or down time.Tour: This would be when you are transferred say to Germany or Korea or Alaska from a stateside assignment. Your tour will last X number of months depending on if your family goes with you if you are married and the location you are going to. When you are say in Alaska, you do your job, say as an MP like my son did. He would work for 5–6 days then get 2–3 days off where he usually had no military duties to perform. That means that he could go into town, go camping, hiking, whatever he wanted within a certain mileage range of the base for his days off. He then had to report back to duty when his time off was done. This is what was used to be known as a pass, something that is no longer used.Leave: This is something that each service man/woman earns at the rate of 2.5 days/month or 30 days/year. This is used as ‘vacation’ time to take longer trips away from your assigned base. Usually to visit home or family members. Most Servicemen take some leave when they PCS or move from one base to another base. Some save their leave and use it as ‘terminal leave’ when they get out of the service, to get out early using their leave time. When I was in and single I was always in the hole or i owed the Army leave time. When I got married I always have leave to spare and was in the position to use it or lose it, meaning you can only have a maximum of 60 days of saved up leave time at the end of a fiscal years or you lose it. It does not look good on a Commander if a Soldier losses leave, so you are ‘forced’ to take it even if you don’t want to to get down under 60 days by the end of the fiscal year.Hope that answers your questions. Hope nothing has changed too much since I retired 23 years ago since that is what I am basing my answers on.Have a great day!!! HOOYAH!!!