A half shadow. The partially shaded outer region of the shadow cast by an opaque object. Also, A peripheral or indeterminate area or group.
Mid 17th century: modern Latin, from Latin paene ‘almost’ + umbra ‘shadow’.
“As I dodged the heat of the day, standing in the penumbra of the large mansion house.”
“The problem is the penumbra of theory expands the potential answer too greatly.”
Itinerant (adj) (noun)
Travelling from place to place. / A person who travels from place to place.
Late 16th century (used to describe a judge travelling on a circuit): from late Latin itinerant- ‘travelling’, from the verb itinerari, from Latin iter, itiner- ‘journey, road’.