What Does Somnambulate Mean?

I'm about halfway through my vacation and having a great time. We've done a little hiking (to a rock climbing area which I, mistakenly, didn't partake in). A little disc golf (in like 30 mph winds, it was not pretty). Thai food, BBQ, local beer, Chilean wine. Mmmm. Temp has been in the low 70's during the day maybe 40-50 at night. Wonderful. My allergies have been killing me the last couple days (cedar pollen is very high). I've been taking Nasalcrom (started over a week ago) plus Benadryl or Allegra to very varied affect. My friends 4 year old is just a riot. For example, we were in the car and he was trying to find a magazine to show me (Bionicle, I think). He said, "Hold on." And I joke "To what?" He paused a second then replied "It's just an expression." Maybe it's just me but that cracked me up coming from a 4 year old.