Pensive

Pronunciation:
\ˈpen(t)-siv\

Definition:
1: musingly or dreamily thoughtful

2: suggestive of sad thoughtfulness

Etymology:
Middle English pensif, from Anglo-French, from penser to think, from Latin pensare to ponder, frequentative of pendere to weigh

First Known Use: 14th century

I have always loved this word. It is very descriptive in a narrow way, much like melancholy.
 
Jack, Chase and I were driving back from Huntsville after seeing a movie and Chase, who was sitting beside me, was very quiet and looking out the window. I patted him on the leg and said, "Chase, you doing okay?" "Yes" was his one-word reply. "Are you pensive?" I asked. "Mom, I don't even know what that means. Good grief, I'm just sitting here."
 
That comment made me pensive. haha!