A "naptime routine" refers to a set of activities or actions that someone does before taking a nap. It helps them relax and prepare for sleep. Full definition
The most important thing about traveling with kids while protecting their sleep, is to be consistent in your approach to the bedtime / naptime routine as well as the way you respond to night wakings and early rising. (healthyhappysleep.com)
Allow time for your baby to establish his or her own naptime routine, and with your guidance, by the time your baby is 6 months old he should be on a pretty set schedule. (day2dayparenting.com)
Use a transitional object (a favorite toy, mom's old T - shirt) to make the crib more inviting, and stick to a soothing, consistent naptime routine. (parents.com)