every ...; at intervals of ...; with ... in between
Attaches to a noun expressing a distance, time period, or number of objects to mean 'every ...' or 'at intervals of ...'. The interval includes the unit itself, so 1日おきに means 'every other day' (with one day in between).
Please take this medicine every 8 hours.
Buses leave for the station every 10 minutes.
We planted trees at intervals of one meter.