Apple - What is parsecd?

According to Little Snitch Research Assistent it is used for Suggestions in Spotlight, Messages, Lookup and Safari and usually connects to api.smoot.apple.com.

Little Snitch 3

Little Snitch 4 (CalendarAgent used for an example)

As described in

/System/Library/PrivateFrameworks/CoreParsec.framework/Versions/Current/Resources/Info.plist

it is location-based suggestions for Siri.